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noob valve adjusting on 1978 280z

This is a discussion on noob valve adjusting on 1978 280z within the Engine and Drivetrain (S30) forums, part of the 1st Generation Z (S30) category; This is going to be long, but I know you guys/gals like data, so I am trying to preempt most ...


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    Default noob valve adjusting on 1978 280z

    This is going to be long, but I know you guys/gals like data, so I am trying to preempt most questions. Well this winter I have been busy. I removed fuel sending unit, which showed me I had 1/2" of rust in laying some places on bottom of gas tank. And the fuel filter was filled up with a lot of rust too (I cut it open of course -and most if it got stuck right to a magnet I put near the pile of rust). So I figured out how to remove the tank (it got cleaned and restored by a pro who does that kind of stuff - washed out, boiled out, acid, and then 2 coats sealer and now its awesome), all the hoses, the fuel pump replaced (put on new original connectors for the new bosch fuel pump), damper assembly cleaned, fuel filter repalced, fuel rail removed and cleaned with carb cleaner, removed and replaced fuel injectors with new good ones (and all the orings too), changed fuel pressure regulator. I replace with all new parts, and all new fuel injection hoses and/or fuel hoses where needed, i cleaned out the long metal fuel rails under car with carb cleaner too, it helped somewhat. Also new air filter, new boots on the AFM both sides....

    Oh yes, also changed oil with castrol 10W40, and put in the datsun/nissan big blue oil filter, and it has new NGK wires, NGK B6ES-11 plugs (gapped to .40)

    Of course, the car runs better now, better than ever before (too long to explain) but its still only getting 10IN of vacuum. :-( at idle.

    Both myself and some local mechanics, used carb cleaner around injectors and intake manifold, and nothing changed. We were thinking maybeI foo-barred some of the orings in injectors, but the engine did not budge one bit with any carb cleaner around intake manifold, or injectors. So it just seems to confirm even more, I dont have any foo-barred orings or intake leaks. I have new quick disconnect electrical connections for the new injectors, just havent had time to install them yet.

    I found a local garage with a smoke machine, and no intake leaks were seen anywhere (and they had an oscilliscope/computer system they clamped onto the main ignition/coil wire). They also said secondary ignition system was looking good on the oscilliscope, firing pattern and burn time looking good/normal. I myself found many little cracked vacuum/pcv hoses and replaced all of them over past month while doing all this other work.

    I cleaned all electrical connections and sensor connections in the engine area, cleaned grounding points in engine compatment where all the ground wires connect to, cleaned fuse box, replaced all fuses. Oh yeah replaced PCV valve, replaced thermotime sensor, replaced water temp sensor, AFM (air temp sensor was bad), replaced thermostat (it was running too cold and now its hot like it should be). I installed a new clear see thru G3 fuel filter after gas tank, after installing new tank back on car. I have a fuel pressure guage currently connected after fuel filter in engine compartment. So I can check it when needed.

    My fuel pressure looks good when starting up, idling, and revving engine. Seems normal to me. Right around 36 psi.

    I probably left some stuff out. But after all this work, the engine is running better then it ever had before, however, I really feel its holding back. I still smell some exhaust even with downward tip extenders (I think those reallllllllly helped a whole lot and only cost 10$)...And lets see, Im getting 7 to 8 mpg in town driving , yes really that bad, and my AFR's from the innovate meter are showing my idling at very lean conditions like 18 AFR or a little higher when sitting at stop sign, and WOT is 10.1 to 10.3, and crusing is around 12.5 average, sometimes almost 13 if I am going in a straight line and barely touching the gas pedal. I drove for 44 minutes and recorded all the data on the AFR meter and played it back on my PC. Several times now.

    The local mechanics checked timing(and changed it as much as they say they could-because of the 10IN of vacuum the engine was only producing), they also played around with the idle adj screw and AFM bypass screw a little bit.

    The also said distributor cap looked good and clean inside, and the distributor itself (what you can see by popping the top off anyway, basically looked OK - but they suggested a removal/inspection/and possible replacement of its 'guts', if needed)

    After all this information I gave them, and the tests they did, they say I need valve adjustment. I have heard that before earlier in this project, but I have wanted to restore car to as much new stuff as I could....and also do as much of it myself. So I have learned a lot over the winter time, and thanks to many people on here to encourge me to do all this stuff.

    However now to the meat of the meal, adjusting valves scares me somewhat that I could royally foo-bad something. I will be careful of course but still....So I was wondering if someone can offer some tips faq watchout problems etc. I saw bits and pieces of information about valve adjustment, but it seemed like they were for older z cars. Dont know how much it applies to my 1978. I have read about doing it hot and cold, and I would plan on doing it cold the first time. And I suppose first of all, I just need to remove rocker cover, and just inspect them in the first place and see whats what. And what their clearances are now.

    !Oh yeah!, I learned how to do compression tests (was about 150 psi on average across all cylinders), but I did it with cold engine and didnt open the throttle (didnt know about it then, and still honestly dont know how to do that exactly), so I read on this site, that doing the tests warm, and opening throttle could add anywhere from 5 to 20 psi. So my compression could even be higher 155 160 170?

    I also learned how to do leak down tests, on average it was 15 to 19% (mostly towards the 19% side) and one cylinder I could only get down to 23%, which all that seems OK to me from what I have been reading. According to the guage up to 40% is in the green, of course I dont really beleive you want to be around 40%, around 20% seems a lot better to me. And I was told that 15% is about normal for any average new(er) car. Ohhh I am sure I left some things out. And I realize just beacuse I replaced all this stuff doesnt mean its all working. But I am gonig to choose to believe it is all working for now. It really seems that if I have some valves that are tired and not set correctly, that my gas mileage will suffer, could smell wierd exhaust problems because of incomplete combustion, and not have the power I believe the car is missing right now. So I am reallly hoping a valve job can bring it back to even have more power and fun!
    Last edited by argniest; 04-15-2011 at 02:58 PM.

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    Adjusting the valves is one of the simpler things you can do. Verify the factory specified clearances for intake and exhaust valves, have the appropriate feeler gauges on hand, 17mm & 14mm open-end wrenches, remove the plugs and valve cover, place car in neutral. Use your crank pulley bolt w/27mm socket to rotate the engine to measure the clearance between the cam and lash pads. Adjust to specs as required. You'll be done in just a few minutes.
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    Wow, looks like you have been very busy! I am thinking that there HAS to be a vacuum leak somewhere. When you did the smoke test, did they just smoke it or did they add a florescent dye to the smoke and check the underside of the Intake. It is hard to see with the heat shield and everything. The florescence will really pop under the 'special' light/goggles. Did you remove the vacuum line going to the AC control valves BEFORE testing? Those valves sometimes will seize and result in a 'open' condition. Are all of the larger rubber hoses (e.g. Brake booster, Aux Air, PCV, etc) nice and snug?? Just asking.

    The valve adjustment is no big deal, definitely something you should do. Do you have an FSM for the '78? I have an one in .PDF that I cleaned and added links to the subject areas (to reduce scrolling), PM me and I'll send you a copy.
    Andrew (ZCurves)
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    Yup, have been busy since last november, thanks to everyone on here too :-) who gave me confidence and great information of things to do. I know it may seem I am throwing parts at the problem. But my plan is to just make everything that I can, renewed. And if I have to get into finer testing parameters, I would rather do it with new equipment. I did test (or have tested) some of the parts that were replaced, and found them to be bad. I also did the coveted fog machine test inside the cabin, which helped teach me some things about venting holes, and other things to 'seal up' to reduce any exhaust coming into the car. I also treated some minor rust issues on some places under the car while the tank was off, like the big metal plate that holds the bumper onto the car. I used the 4 step eastwood chemical/paint process for that, and for the outside of the gas tank, so my tank is chassis black (satin) and looking like new or better. Ooooooh well....

    Yeah I cant believe I am getting 10IN of vacuum for no reason :-O....it does make sense to me, with what I understand about the engine now, that having the valves adjusted could really help a lot. But first I just need to open rocker cover, and just measure them and see where they are at. And who knows what else I will find. Hopefully everything will be in good order, and just need some minor adjustments. Actually I did have the rocker cover off once before at a local mechanic, wayyyy long time ago in this process. We didnt see anything out of place. But didnt get into any details, he just did a quick measurement of a few things.
    Last edited by argniest; 04-15-2011 at 07:47 AM.

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    1. Yup, I know about rotating the crankshaft pulley :-) I had to crawl under the car a lot, when I was doing the leak down testing, to get all pistons into an TDC position. Well at least close enough to TDC to give me good readings. I realize that maybe it wasnt at exact TDC, but it was very close. I found a 27mm socket to use. So that will be easy for me to do during a valve inspection.

    2. No, they didnt add dye. I will call them and ask if they do that. I have those goggles and lights that I used for a different vehicle. Thats a good idea thanks!

    3. Did you remove the vacuum line going to the AC control valves BEFORE testing? Those valves sometimes will seize and result in a 'open' condition.
    I dont know about this, where is it? Can yuo tell me a little more about this.

    Also, if I didnt mention it, I also dont have heat coming out of the vents. No matter what setting I put the controls in the car on. The air isnt stone cold either, but I can detect a tiny amount of warmth in it. I mean a very little.

    I have been stuyding about that system a little bit, but its somewhat of a lower priroty right now. I have an IR temperature meter, and I checked the hoses (the short red one, and the black one) that run through the firewall of the car, and the temps are like 150 to 160 degrees in those hoses. (also, I recently replaced the tstat and gasket, and that made my engine temp gauge go back up to the middle range, and the temperatures are like 180 to 185 degrees around where the top radiator hose goes into radiator, so I believe that part os the car is now working correctly). That tells me I am getting heat into the heater core??? but something else is amiss with something inside the cars heating components. Thats a whole area I dont know much about yet....But I also believe a low engine vacuum condition, could be the culprit in the heater, because I thought it uses vacuum to operate some switch/diaphram to let heat flow. So maybe the heater isnt working, just because vacuum of 10IN isnt enough to allow it to operate properly.

    I cannot say if it ever operated at all or normally. I guess I just cant remember everything :-) The car sat for last few months of 2008, was being repaired in 2009 and 2010 by my cousin who restores cars. I have many other posts on here that explain all the other work that was done on the mechanical stuff on the car. In between some of that work, he asked me to test drive it. So, its almost like new now from a total car perspective. If a valve job would help bring the engine back to more normal operating parameters, that would be soooooooooooooooooooooooooooo awesome!

    4. Are all of the larger rubber hoses (e.g. Brake booster, Aux Air, PCV, etc) nice and snug?? Just asking.
    I would like to say I am 100% sure about all of those hoses, but you never know. I have tried to check every connection on the intake hoses. Doesnt mean I missed one or two. I will go back through and dbl-check them all this week, its gonna be raining a lot I guess. So I dont get to do any test drives anyway. That was another reason I wanted to find someone who had a smoke tester. They left it on there for 4 to 5 minutes maybe?, and none of us saw anything. It doesnt mean that wasnt a leak, but if there was, it had to be very minor...however, looking at the underside of car, and just in general, after using dye would be useful!

    5. Do you have an FSM for the '78?
    Yup I have the nissan 750 page long original FSM, and another really good one from clymer from 1979 that has great information and some procedures explained better for my brain anyway. And I have the electronic pdf files I got off the internet. And several of the great sites referenced from people here. I am always reading these materials all the time. In a quest to learn everything that I can about my car.
    Last edited by argniest; 04-15-2011 at 08:10 AM.

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    Quote Originally Posted by argniest View Post
    Also, if I didnt mention it, I also dont have heat coming out of the vents. No matter what setting I put the controls in the car on. The air isnt stone cold either, but I can detect a tiny amount of warmth in it. I mean a very little.
    Quote Originally Posted by argniest View Post
    But I also believe a low engine vacuum condition, could be the culprit in the heater, because I thought it uses vacuum to operate some switch/diaphram to let heat flow. So maybe the heater isnt working, just because vacuum of 10IN isnt enough to allow it to operate properly.
    That tells me a lot, I am really leaning toward it being from vacuum leaks at the Magnet Valves. When these are inoperable the Heating and AC will not function properly. These valves control the Fast Idle and the Mode Doors inside the dash. So although you performed needed maintenance on the Thermostat, the Mode doors are not opening to let the heat flow into the cabin - same would be true for the AC.

    The AC/Heat controls in the dash need to have a vacuum to operate and that is supplied via the Vacuum Reservoir and the Magnet Valves. In your FSM, refer to pages AC-13, AC-36, AC-37

    Quote Originally Posted by argniest View Post
    If a valve job would help bring the engine back to more normal operating parameters...[SNIP]
    I think that you are mean Valve Adjustment. Valve Job is a different task and a much more drastic step.

    I have to mention that from reading your previous posts that you are being too modest in regards to your Z Car knowledge. You have done quite a lot and I for one am very impressed.

    Good Luck & Post Pics,
    Andrew (ZCurves)
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    Hi Argneist,

    It sounds like you're getting to the point where I was a while back. You've done a LOT of work and your engine still isn't right. Cozye got to a similar point, and we sort of worked through a common solution together. It turns out that our ECUs had drifted in their timing properties over the decades, and so we had to trick them about coolant temperature in order to correct their timing. You can read all about it in this very long and meandering thread:

    http://www.classiczcars.com/forums/s......&highlight=

    Somewhere buried in there is my "yogurt cup test," whereby you remove the AFM, stuff a yogurt cup into the AFM/throttle boot, place a hose on the vacuum booster nipple, and blow on the hose with your mouth to "inflate" the entire intake system. A bit of air will leak out, but if the intake is tight, it won't be much. It's a very quick way to confirm that you've found all your vacuum leaks (rather than searching endlessly for a leak that might or might not be there). Once you've put the vacuum leak issue to bed, you can move on to other issues.

    Anyway my engine wasn't running quite as badly as yours (judging from vacuum numbers -- mine being maybe 14 in Hg initially), but I was able to get my engine running quite well by adding resistance to the coolant temp sensor circuit (thereby correcting mixture). I now run with about 18.5 in Hg. Cold and warm running are quite good. I think I'm just a tad on the rich side, but better rich than lean. (I can adjust the mix leaner with the turn of a screw if I want.) My engine almost always starts in less than a second (1 revolution?) and runs strongly. The only exception is if it's been running and sits for about 20 min, during which time it becomes heat soaked and might take a few revolutions to start. Mileage is about 19 or 20 combined, and more towards the upper 20's on the highway. The magic that made all this happen is a little resistor in series with my coolant temp sensor. :-)

    Anyway, study the thread I linked, and you'll see how Cozye and I systematically went through all this stuff. (He achieved similar results, BTW.)

    Oh, and don't worry about the valve adjustment. It's a very easy and strangely satisfying undertaking. You'll be working on the most beautiful part of the engine, IMO. Just don't get your hopes up that it will awaken the beast in your engine. It probably won't make a huge difference, but it definitely needs doing from time to time. Enjoy!
    Last edited by FastWoman; 04-15-2011 at 03:03 PM.
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    Thanks Andrew for the compliment (and do you have a 1978 280z also, in 510 blue? it looks like you might). Yes, I did mean a valve adjustment and not valve job :-)...I just corrected that hehe. Yup, I have done a whole lot of things to my Z car to make it as new as possible. I also have completely gutted the inside of the car and put it back together now, soundproofed it with some dynamat, fixed a door lock problem so I can unlock the door now, sealed some new plastic sheets in front doors to seal them off, and dynamat in some places. The car is queiter because of all this, I fixed some small surface rust issues in a few places in the car, and other little stuff too. Put in a new electronic antenna back there. Installed a custom made 6 x 9 speaker box that looks like it belongs back there in the car, installed new 4" speakers in the side holes behind drivers head. The stereo sounds great, and its not even barely getting started. I spent months designing a very nice system for it. Just waiting to get engine running right, then I will move onto that someday hopefully sooner than later but who knows.

    HA Its like the last 6 months just vanished. I have like four levels of tasks to do, I am basically done with level 1 and level 2 which are the more serious stuff, and am playing around in level 3 and 4 stuff I imagine for the next year. Tracking down some wierd things like non working side marker lights and no hazard lights.

    Also, I am going to install a new backup light switch soon, its kind of leaking and also has a wire broken on it. Im getting way off the subject, sorry its hard to not talk about all this stuff I have done. I am proud of myself for being patient, reading and learning and DOING, and thankful for everyones help to get me to this point

    WELLLLLLLLL ANYWAY
    If this valve adjustment brings the car MORE power and life, and better gas mileage, I will be very happy! you cant even imagine! I need to study up on exactly how to do the procedure. I know its easy for anyone who has done something like this before, but staring down the gun barrel when you have never done anything like that before, its a little intimidating. And by gosh I dont want to do any harm. Only good! It is sounding like I shouldnt except a whole lot from adjusting valves. It would be nice if they were in spec, but that only leads to other problems. So it is what it is...somewhere there is a monster hiding and I wanna nuke it.

    I also just read the new post right above here. Ohhhhhhh wow, that is very interesting about the yogurt cup test. I need to do that for sure like RIGHT AWAY this weekend. Its making me about MAD, wondering, hmmmmmmmm does my Z car have a vacuum leak or not. I want to get it behind me JUST LIKE YOU SAID. Even tho those mechanics and their smoke test machine didnt blow smoke out anywhere, I jsut cant seem to let go of the fact that maybe there is still a leak somewhere.

    Also, I can somewhat understand what you are saying about the ECU drifting away from its specs, and you had to figure that out and how to compensate for it. I hope that is within my reach. I need to read your thread and see if that is something I can do too, something to do, if I need to do it. It could explain a lot. but I havent eliminated other variables yet like the stinking TVS. grrrrrrr too many things to do. But at least I have learned a lot this winter, and done a lot to make things better. And limit scope of the problems.
    Last edited by argniest; 04-15-2011 at 03:33 PM.

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    Just one other funny thing, is since I restarted it for the first time a few weeks ago after finally getting everything installed (it started first time BTW -after an ordeal with getting the fuel pump primed, all I did is remove gas cap - hehe) I have taken it on test drives. And almost everywhere I go, I catch people turning their heads, they talk to me at stop lights, want to race me, give me thumbs up, want to buy it, etc etc etc. I want to get it running so good, so bad !!!!!!!!!
    Last edited by argniest; 04-15-2011 at 09:08 PM.

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    Quote Originally Posted by FastWoman View Post
    Hi Argneist,
    It sounds like you're getting to the point where I was a while back. You've done a LOT of work and your engine still isn't right. Cozye got to a similar point, and we sort of worked through a common solution together. It turns out that our ECUs had drifted in their timing properties over the decades, and so we had to trick them about coolant temperature in order to correct their timing. You can read all about it in this very long and meandering thread: http://www.classiczcars.com/forums/s......&highlight=
    WOW thats a lot of interesting information about the resistors etc. I just finshed browsing thru all 4 pages. Nice. Its good to know there are things like that to try out if needed. I am hoping I will get lucky and be up and running without crazy stuff like that :-) However, I will be doing the yogurt cup test just as soon as I can. That sounds brilliant!

    I am pulling the rocker cover off in a few minutes because I cant wait until tomorrow...and found this great article too http://www.picturetrail.com/sfx/album/view/1803105 about doing the whole procedure. I need to go pickup a remote starter tomorrow and one of those crows feet wrench tips.

    I was thinking I was going to be crawling under the car like before when I did the compression tests and leak down tests...to advance the crankshaft pulley with my 27mm socket. But the remote start will make it painless. nice! If I need to tweak position of crankshaft a tiny bit I can always get under there and do it manually like before. AND YES I WILL KEEP IT IN NUETRAL SO I DONT RUN IT THRU THE BACK OF THE GARAGE....
    Last edited by argniest; 04-16-2011 at 10:37 AM.

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    Valves are at the top of the engine, oil sits in the bottom of the pan. No need to drain the oil.

    By the time you get to the last valve, you'll be an expert and will want to recheck them all.
    Gary
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    If you want to adjust your valves, look on Blue's tech tips for Kammy's procedure. I found it rather easy to follow.
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    Quote Originally Posted by SteveJ View Post
    If you want to adjust your valves, look on Blue's tech tips for Kammy's procedure. I found it rather easy to follow.
    Yup, that is the site I was looking at, and they showed draining oil. I was a little baffled why that was part of the process, because as I understood what happened to oil, would not require draining it. But hey, I just thought I should ask before diving in.

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    Sounds like great and satisfying progress. I enjoy reading your humble and ,yes, informative posts. I have a few suggestions regarding low vacuum as I had a couple of the same issues you have experienced.
    "no heat"- I only had airflow from the console center vents. No floor or defrost. I found a cut in the line from the magnetic solenoid valves that supplied vacuum to the vacuum diaphragm valve, over the driver-side footwell. I had to remove the solenoid bracket to turn it upside down (passenger wheel well/engine bay) to find the cut. Not that I knew it (cut) was there, I just couldn't see every inch of tubing. Bingo! Flow control! But no heat. A little, for a few minutes as the thermostat opened but it quickly faded. More tracing of vacuum lines. Back to the mag solenoids. I rationalized (with the vac schematics) that I could troubleshoot the mode doors and vacuum valves under the dash by doing some temporary re-plumbing. Guess what? A cut that I missed. Right at the other mag valve. That leak kept the mode door in the "direct airflow over the a/c evaporator core" mode" vs. "direct the airflow over the heater core", which seems to be the default for the vacuum diaphragm valve above the passenger footwell. Hope that helps.

    Secondly, check your oil fill cap on the top of the valve cover and the fitment of the dipstick. Easy for both, with the engine running, remove the dipstick. Put your thumb over the tube. If your vac gauge reading improves, the rubber on the dipstick isn't providing a good seal. Just removing the dipstick with engine running should change the sound of the engine. With your low vacuum, I wouldn't be surprised if it stalls. Same with the oil cap.

    Kris

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    Yeah Kammy is great guy! He actually shows a full tune up in that procedure. I believe the datsun maintenance interval instructions are to do a valve adjust with each oil change thus the grouping. I think he may also do timing too.

    Not a Z but I like this guys go/no-go technique on a Honda S2000 using feelers: http://youtu.be/dwjbGPYGlyo
    Last edited by Blue; 04-16-2011 at 01:26 PM. Reason: 4th video
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    well guys and gals here are some results. I removed valve cover tonight and got the feeler guages out. These are two things I have never done before. So I did this several times. Oh yeah I started out by using a remote starter switch which I also never used before. But I determine it turned the camshaft too fast, too far. SO I took that off and hooked up a big old wrench to the alternator "nut". And by turning the alternator "nut" I was able to spin the camshaft around in a lot smaller movements, which allowed me to move the cam lobe "the bunny ears" to be pointing straight up for each valve that I was testing.

    Once I figured that out, I finally got comfortable (I think he he) to measure each of the valve spacing on all 12 valves. I made sure to pay attention to which valve went to which place intake or exhaust. You can tell of course, just by looking where it goes to, like the fuel injector is right there by intake manifold for each intake valve, and exhaust valves, well they are by the exhaust manifold which is lower than intake manifold basically.

    I did it two times just to verify the numbers. I found that for instance, I could not stick in a .013, but the .012 could go in and out of that space with a little tension on it, but not a lot.

    PS I have the 1978 280z 5 spd. Just as a reminder.

    I did this with engine stone cold

    So here are the numbers. I will number them from 1 to 12...starting at the front of the engine for cylinder #1, valve 1. (I)ntake valve and (E)xhaust valve.
    1(E) - .012
    2(I) - .007
    3(I) - .008
    4(E) - .012
    5(I) - .008
    6(E) - .012
    7(E) - .011
    8(I) - .007
    9(E) - .011
    10(I)- .007
    11(I)- .007
    12(E)-.012

    Can anyone tell me if these numbers are OK, bad, really bad?? I dont know what tolerance the engine has to run with these numbers, and if they are bad enough to warrant causing my vacuum to be lowered a little, medicore, or a lot.


    PS WilloughbyZ: That is all really great information, but I know nothing of any of that part of the car right now. As usual, everything like that I get into is brand new to me. I do have the FSM, and the clymer datsun manual from 1979 which has been really helpful for some things so far. So I can certainly look those things up. Do I have to take the dash out to see those things you are talking about.

    What I am thinking about is this...could I just temporarily PLUG UP the vacuum lines that feed the HVAC system? I mean if there was a place outside the cabin of car (that is in the engine compartment somewhere) to cut the lines and plug them off in the engine compartment before they run into the car...so if there was a vacuum leak inside the car, at least I could more easily limit the scope of the problem. And then deal with it later. I can live without Heating and AC (I have factory AC that was working last year, but I havent even tried it yet this year, been too busy messing with a 100 other things as you can tell). But I am dying to find the source of this missing vacuum. Im at like 10 IN right now. And from what I remember, it was a fairly stable 10 IN, but not dead on 10IN the entire time. So I guess what I am saying is it wobbled a little bit from 10IN. ANd I dont know how rock solid a normal running Z car's vacuum pressure should be.

    I know its way too low, and is making me about crazy now, to figure out what is going on and why. If you look at this point here, you will see the condition of my spark plugs just after a few hundred miles of test drives, and gonig to those few mechanic friends of mine.

    Also I know the defrost worked before, but it seems like when I was playing with it during one of my two test drives this year after getting it started up again, that the defrosters did not come on. I can only say for sure the two vents in the center console were blowing air. I will verify next time I start it up, if any other vents are blowing air.

    THANKS
    Last edited by argniest; 04-17-2011 at 10:21 AM.

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    Well, your intake valves look a bit tight -- should be gapped to .010. The exhaust should be gapped to .012. Although the valves need a bit of adjustment, I don't see anything alarmingly out of align that would screw up your compression.

    You shouldn't assume that low intake vacuum indicates a leak. Remember that your biggest vacuum leak is the throttle body, and it's supposed to be there. Engine vacuum is a reflection of the running efficiency of the engine.

    You can test your HVAC vacuum tubing for leaks simply by removing the supply tube from the intake manifold (near the brake booster vacuum line) and sucking on it. You'll be able to feel whether it's tight. If you want to disconnect it for testing purposes, just leave the tube off, find a small piece of tubing the same size, put it on the nipple, and then plug the other end of the nipple with something like a golf tee.

    Did you do the yogurt cup test yet?
    Last edited by FastWoman; 04-17-2011 at 08:27 AM.
    My last three sports cars while I still owned all three:

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    Well the numbers were done when stone cold, and arent they supposed to be .008 for intake and .010 for exhaust? So based on that, would these numbers be bad enough to cause running/vacuum problems in the engine? And no, I didnt do the yougurt cup test. I just really wanted to see how my valves looked, even if I didnt adjust them yet. So I had some idea if they could be the source of my low vacuum condition or not.

    This will seem dumb, but since I currently have the rocker cover off, can I do the yogurt cup test with that off. I mean the engine is all interconnected, and I just am not sure if having it off would effect that test or not. Because some of the intake valves could be open...

    Are you talking about pulling off the vac line #1 in my pics? And capping it off, then I could eliminate any possible leaks happening from the HVAC system, or should I say it would eliminate them from the equation. And limit down the scope of any vacuum leaks. Those guys smoke tester did not send any smoke out anywhere. But I also didnt look inside the cabin like under the dash where I suppose these lines are coming in.

    And BTW, what is Vac line #2 in the picture. I am not sure what that is, but its running side by side with the other one.
    Attached Thumbnails Attached Thumbnails noob valve adjusting on 1978 280z-hvac-vac-lines2.jpg   noob valve adjusting on 1978 280z-hvac-vac-lines.jpg  
    Last edited by argniest; 04-17-2011 at 10:36 AM.

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    The rocker cover has to be installed to do my yogurt cup test. When you do this test, you'll be testing for tightness EVERYWHERE. This will include rocker cover, oil pan, oil filler cap, dipstick, intake manifold gasket, several closed intake valves, the piston rings and exhaust valves on the other side of one or two open intake valves, etc. The test won't pinpoint where you have a leak, but it will certainly confirm whether you have a leak that you need to track down.

    Cold valve lash measurements aren't as reliable as hot measurements. Having said that, I suppose your exhaust gaps look a bit loose and intake gaps OK. Still needs adjusting, but nothing too far out of the ordinary. I wouldn't expect much improvement in the running condition of your engine from the adjustments. Your engine might run a tiny bit quieter -- less ticking. I doubt you'll gain much, if any, engine vacuum.
    My last three sports cars while I still owned all three:

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    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    If it aint broke dont fix it . I definately DO NOT want to mess with the valves if I dont have to right now (for a noob, that is an uneccesary risk I do not wish to take if it isnt going to make that much of a difference). If adjusting them close to specs as I could get them isnt going to give me much improvment, then for now, I think I need to focus else where. I know, there are a 1000 things that could be causing this, and it seems we are saying I have eliminated the valves as the source of why I am at 10IN of vacuum? right?

    The wierd thing about all of this, is that the engine sounds and feels better than ever, but I know its not right yet, and omg its getting like 7 to 8 mpg. And those AFR's numbers are not good either. Which I wouldnt expect them to be. And then the spark plugs, I posted a picture of them on my other thread about the AFM.....sigh! Can I beat my head against a rock now!!!!!!!!!!!!!!!!!!

    Oh yeah, I do hear a little tapping under the rocker cover... so those exhaust valves being .002" off, could be the cause of it?
    Thanks!!!!

    Plug picture http://www.classiczcars.com/forums/s...l=1#post361195
    Last edited by argniest; 04-17-2011 at 10:53 AM.

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    Yeah, those exhaust valves could be part of the tapping. However, this engine will never sound as quiet as an engine with hydraulic lifters. It's going to tap very softly even when in perfect adjustment and perfect running condition. That's the nature of the beast. Nothing to worry about.

    Personally I'd adjust the valves while you've got your tools out. Adjust a few valves while cold, just to get the hang of it. Then put the cover back on, run the engine until warm, and do the warm/hot adjustments. You won't break anything. Trust me that you're being much too fearful of this job.

    But no, I don't think your valves are the source of the 10 in Hg vacuum, at least by themselves. They might make a small contribution, though. I suspect low vacuum in most engines has at least several causes.
    My last three sports cars while I still owned all three:

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    Yup, I admit it, I am VERY fearful of actually touching the engine. Its one thing to replace external parts like fuel injectors, fuel tanks, and fuel hoses, but a whole other thing to mess with the parts of the engine itself. I WANT TO DO IT, but I dont want to mess anything up. like 1000x.

    If those valve readings I took are not likely to cause much of my vacuum problem, I really want to wait and do it later. It seems there are too many other things that could be causing my problem. Now that we know where my valves are at.

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    Honestly the solution to getting your engine right might be the systematic correction of a whole bunch of little problems like this one. Do this: Leave your sledge hammer in the tool box, along with the crow bar, pliers, and vice grips. Pull out some fixed hand wrenches (no crescent wrenches!) of the appropriate size, as shown in the slide show. (No, you don't NEED a crow's foot wrench. A regular hand wrench will do.) Now, with the tools you have in hand, I don't think you're strong enough to break or screw up anything!
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Quote Originally Posted by FastWoman View Post
    Honestly the solution to getting your engine right might be the systematic correction of a whole bunch of little problems like this one.
    Yeah, I have to believe that is exactly what is happening, a whole bunch of little problems. and maybe bigger ones that I caused when I repalced FI's. Here is what you said:

    "1) I pulled off the AFM and plugged the AFM-to-throttle boot with a yogurt cup. I pulled off the vacuum booster line to the brakes and attached a hose to blow through. I pressurized the intake with nothing but moderate lung power, held the pressure with my mouth, and got a feel for how long it took for the pressure to leak away. I then pulled the little HVAC vacuum control line (adjacent to the power brake vacuum line) and repeated the test."

    I dont see how a yogurt cup would plug that space up? It seems like the hole is 2x thats size? Where is vacuum booster line? I just want to make sure I am doing the right thing here....And you are saying to take the AFM off the car. It seems with a yougurt cup in there, and then blowing into the intake system, isnt that just going to push the yogurt cup right out of there whenI start blowing into the hose I would attached. I know....more stupid questions.

    I ATTACHED A PICTURE OF WHAT I THINK YOU ARE TALKING ABOUT, CAN YOU TAKE A LOOK AT THE PIC, THANKS!
    Attached Thumbnails Attached Thumbnails noob valve adjusting on 1978 280z-yogurtcuptest.jpg  
    Last edited by argniest; 04-17-2011 at 12:03 PM.

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    I suppose it depends on which brand you buy! I don't think Yoplait is large enough. Maybe Yotastic or Danon, which comes in the squattier cup. But it doesn't really have to be a yogurt cup. Just find something that will plug up the boot. Maybe a rubber ball or a juice glass?

    And yes, you've got it all right (in the picture). You don't have to plug the hose up. You can just leave it hanging.
    Last edited by FastWoman; 04-17-2011 at 12:21 PM.
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    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Quote Originally Posted by FastWoman View Post
    I suppose it depends on which brand you buy! I don't think Yoplait is large enough. Maybe Yotastic or Danon, which comes in the squattier cup. But it doesn't really have to be a yogurt cup. Just find something that will plug up the boot. Maybe a rubber ball or a juice glass?

    And yes, you've got it all right (in the picture). You don't have to plug the hose up. You can just leave it hanging.
    DING DING DING we hhhhhhhhhhhhhave a winner

    OK, but what about this question. I will find a 'something' to plug up the hole...but when I start blowing into that hose, isnt it going to make the yogurt cup go flying out of its hole? Should I slap some tape over the yogurt cup to make sure it stays in there while doing this pressure test?

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    Sure, you can fortify with some tape or simply hold it in place with your hand. In my experience, if you wedge the cup in there pretty well, you have to blow quite hard before the thing pops out, but with a bit of lung power, you can do it.

    Incidentally, I save my squatty yogurt cups for mixing epoxy and other odd uses, so I always have a stack of them in the garage. That's why this test famously became my "yogurt cup" test.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Well thanks! I just wanted to make sure I was understanding how to do this test. I think I do now. So once its decided if I should/can just leave valves alone for now...I would rather do other things that dont involved internal engine parts. I cant stress that enough :O

    Things like yogurt cup test, removing HVAC vacuum lines out of the engine vacuum loop by temporarily disconnecting them, by removing spark plugs and Fuel injector connectors, one by one and listening to what happens. I can always adjust valves later. After doing a bunch of other things.
    Last edited by argniest; 04-17-2011 at 02:01 PM.

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    Quote Originally Posted by argniest View Post


    PS I have the 1978 280z 5 spd. Just as a reminder.

    I did this with engine stone cold

    So here are the numbers. I will number them from 1 to 12...starting at the front of the engine for cylinder #1, valve 1. (I)ntake valve and (E)xhaust valve.
    1(E) - .012
    2(I) - .007
    3(I) - .008
    4(E) - .012
    5(I) - .008
    6(E) - .012
    7(E) - .011
    8(I) - .007
    9(E) - .011
    10(I)- .007
    11(I)- .007
    12(E)-.012

    Can anyone tell me if these numbers are OK, bad, really bad?? I dont know what tolerance the engine has to run with these numbers, and if they are bad enough to warrant causing my vacuum to be lowered a little, medicore, or a lot.

    THANKS
    For a cold engine your intakes tends towards a little tight and exhausts loose. Clearances should be:

    Cold:
    Intake .008
    Exhaust .010

    Hot:
    Intake .010
    Exhaust .012


    Every manual that I've read that makes note of the difference between cold and hot strongly suggests adjusting the valves only when the engine is hot. In an ideal world, the only time you adjust valves cold is after a rebuild. And then after getting the engine installed and running, adjust them again while hot. You seem willing to put in the time so I'd suggest doing them twice. Once, cold to get them close (and for practice) and then after driving around for at least 15, preferably 30 minutes, do'em again while hot.

    The tight intake valves could lower your vacuum as they are effectively being held open to long and the compression stroke could be pushing the charge back into the intake manifold. The exhaust valves, I'm almost willing to bet, is the cause of your lousy gas mileage. They are not opening deep enough or long enough to allow the burnt gases to escape. Your injectors are sending in the gas expecting it to burn with X amount of air but effectively you only have X-Y, where Y is the volume of burnt gases, of air to combust.

    Since you have a manual, you don't have to bother with giant sockets or remote starters. Just put it 5th and push. If that's a little too difficult, loosen a few plugs (mark the wires first, please!) and you could push it to Kansas.

    Don't sweat it. You far more ambitious than I have been and about the worst that can happen is getting a nasty cut/bruise on a finger when loosening a nut. Just be sure to write down which one's you've done and tighten the, whatever the hell the bigger nut is called, the securing nut will do, back after turning the other nut to adjust the clearances and you'll be fine.

    Chris

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    well, what I would like to do as soon as I can, is to run the car around for 20 minutes get it warm, and bring it home. Pop off valve cover, and take measurements when they are still warm/hot. I think it will be good to have that data too. And see what kind of differences I spot between the clearances between cold and hot. And then comes the fun of adjusting them. Now that I have removed and put back on valve cover, and also closely inspected everything in the valve train of the engine, I mean it all looks in good shape. Everything seems consistent, and no loose pieces laying around like some people found in their own Z car engines. It was fun spinning the camshaft around (i used a big wrench on the alternator nut) and I could watch the valves opening and closing and rocker arms moving. I mean this is the first time I have ever seen any of this, so while that seems silly and trivial, it was really neat to see it all first hand for the first time. It taught me a lot. Now I know what the cam lobes are, the rocker arms, the intake and exhaust valves and springs, the lash pad. And the spring clips on the rocker arms.

    I still dont know if I will adjust them myself or not. I would rather do it myself, but I might ask these local mechanics I met, who seem pretty knowledgeable, and are nice to me, patient with all my stupid ignorant questions. But then again, I did offer to pay them to put up with my questions. I am on the clock when I am there, even if we are just talking. I figure its only fair to pay them for their advice. ANd they dont mind if I hang out with them while we were doing all that other smoke testing, scope testing etc. SO they might let me even do some of the adjustments myself. Like have them do one, and me do one, have them dbl check while I work, etc. I would feel a lot better the first time, to have a pro there. This is not something to take lightly. One mistake and I just cost myself inummerable heartaches of money and wasted time waiting to get a blown up engine fixed.


    Jetaway: do you really think if my valve clearances are only that much off, that it could wreak that much havoc on my engine? And do you think my valve clearances as stated, could be making engine vaccum only 11 IN when idling at 900 rpm, and 14 IN when I set idle at 1500 rpms?
    Again since I dont know how tolerant the engine is for .001 off the mark or .002 off the mark on exhaust, it didnt seem like they were in bad shape to me. But I am only about as smart as a 2 watt light bulb right now.
    Last edited by argniest; 04-18-2011 at 11:20 PM.

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    argniest, yes my Z is a '78 and 510 Blue (to answer your earlier question). Sorry I did not respond earlier as I have been lurking - no need to post when you have been getting all of this great advice! When you get done adjusting the valves, you can come to Houston and do mine - after all of this I think I could certainly trust you.

    For the HVAC vacuum question way back on post #18, The fitting you marked as #1 is the one to block off. #2 is for the AC Fast Idle and is controlled by one of the Mag Valves.

    Did you check ALL of the little EGR related vacuum hoses?? Just had to ask.

    BTW - When I was young and just learning to work on cars and something or some task would be kicking my Arse, my father would remind me not to get frustrated and angry, but to put my tools down and take a break. Walk away for a while, get a drink, rest your hands and clear your head. It was hard sometimes because I wanted to resolve the issue. Just a reminder.

    Finally, Why were you posting at 1:14 in the morning?! Go to bed!
    Andrew (ZCurves)
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    Im a late nighter, always have been since the day I was born. My software programming work can keep me up until 2 and 3 am, so 1:14 is actually early for me. And yes, while I get frustrated, I have never been actually mad about any of this project. Its just like the best carrot I can ever imagine, dangling just out of my reach. Every day it taunts me and teases me. And in order to get it, I have to do so many new things, and learn so many new things, things that take a lot of time, and then finally someday I can just walk over and grab the carrot and devour it :-) Its good advice what you gave tho. Thanks.

    Yes, I have checked all vacuum lines, hoses, etc. And the smoke tester we used too, would have shown any important leaks. Im still going to find out if they can put dye in it. My todo list is huge again. :O And the HVAC system has been temporarily removed from the vacuum loop in the engine by dosconnecting said hoses and plugging off the port hole in the intake manifold either with a vacuum guage or a hose with a plug in the end of it. I also removed brake booster vacuum line too, just to make sure that wasnt effecting anything. And nope didnt make any difference in engine vacuum. I know I need to break out the multimeter and do some serious testing of things, especially related to FI connectors 6,5,4. I feel like a spinning top, I got to stop spinning around and take some more things off my list

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    Right now, you have some of the best advisors available from this site, watching over you and providing insight,suggestions and experience. IMO, they are here and responsive to you because you do your homework and you follow instructions (usually). I say usually, because if you don't adjust your valves as your next step, well, I may just stop following this thread! Damn, son! Just go for it!
    Chris (Jetaway) couldn't have said it better as to why you can't put it off (valve adjust) any longer...

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    There is a check valve on the brake booster hose. Did you remove the brake booster hose where it connects to the intake or at the booster?
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    Quote Originally Posted by argniest View Post

    Jetaway: do you really think if my valve clearances are only that much off, that it could wreak that much havoc on my engine? And do you think my valve clearances as stated, could be making engine vaccum only 11 IN when idling at 900 rpm, and 14 IN when I set idle at 1500 rpms?
    Again since I dont know how tolerant the engine is for .001 off the mark or .002 off the mark on exhaust, it didnt seem like they were in bad shape to me. But I am only about as smart as a 2 watt light bulb right now.
    In a word, yes. I was very busy with work when I bought my Z and a student (college) whose family built race engines (American, not a Z's) offered to adjust the valves for $30. I said, OK as he could do it while I was at school. Clattered all the way home. I parked the Z for a couple of weeks and when I did adjust the valves it had a lot more power. Do I know for an absolute fact that tight intake valves cause low vacuum? Nope. But they could. You shouldn't think just in terms of the absolute measure -- .001 or .002, but in terms of percent. Your intakes are 1/8th or 12.5% tight and the exhaust somewhere between 20% and 25% loose.

    Bit more ominous, isn't it?

    Your engine may have other problems but until you get the valves adjusted correctly, your diagnostics are as likely to lead you down a blind alley as solve any problems.

    Chris



    Chris

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    Chris, dunno... I'm a bit skeptical these errors could make THAT much of a difference, but I don't know for certain. I mean 11 is a pretty low vacuum reading, and three of his cylinders are essentially nonfunctional. (Perhaps the last part about nonfunctional cylinders is in another thread.) FAIW, when I bought my car, two of my exhaust valves had almost no clearance at all. I'm somewhat amazed they weren't burnt. I can't say the engine was running great then, but I can say my putting the valves in proper adjustment did little more than to quiet the valve train just a bit.

    But Argneist, just do it! We're all rooting for you! You're our rock star! You have in your hands the collective karma of the Z universe, so nothing can go wrong!
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    Quote Originally Posted by Blue View Post
    There is a check valve on the brake booster hose. Did you remove the brake booster hose where it connects to the intake or at the booster?
    I removed it from the larger metal nozzle that sticks out of the back of the intake manifold. Did I boo-boo that? Where are you saying to remove it if not there? I guess I should look in manual tonight to see if I can find whatcha are talking about :-) so many things....

    On page BR-15 of the FSM they are talking about this check valve. SO now I think I know where its at. But can you explain where I should have disconnected it? ALso in FSM Fig BR-32, and BR-33 are talking abut this check valve.

    The picture below shows a red arrow of where I think this check valve is at. Now I just need to know more about where I should have tested this
    noob valve adjusting on 1978 280z-brakebooster2.jpg
    VAVLES
    Also, I will tackle the valve adjustment as soon as I can. I make be taking some more work days off just to work on Z car a bunch of days in a row. Tommorrow I am going to hook up a noid light and the spark plug tester that has a clamp on it, and sparks in the middle of it, and go one by one from 6,5,4,3,2,1 and check that I have spark, the quantity and intensity of it (as best as I can judge it), and also watch the noid light. Now I have never used one before, but I am hoping the one I saw at harbor frieghts tools will fit first of all and isnt a piece of junk. Their leak down tester from harbor freight looked nice and all, but didnt work. I bought a better one from amazon and it worked exactly like the youtube videos talked about.

    So I will hook up noid light to 6,5,4,3,2,1 also, one by one. Im not gonna shock myself either. I will pull off the spark plug boot hook up to tester, hookup noid light, and start car....and watch and learn, and then just stop car, hook up next plug and FI, and just see how it all goes.

    FastWoman: I am still mesmurized by the fact that it really seems like 3 cylinders are not working very much at all. I mean you pull that fuel injector connection off from 6,5,4, and it does nothing to sound of engine, but goto 1,2,3 and pull it off, and immeidately slows down a lot, and speeds up to original speed when you put it back on. I mean there has to be something electrical going on here. Its not that I dont think valve adjustment is important, but this 6,5,4 problem, seems a lot more sinister to me. I noticed the dropping resistors control 4 of the injectors and 2 of the injectors. I was hoping to find they would have controlled 1,2,3 and then 4,5,6. I also havent cleaned those particular connections. I know where they are at, but was about the only ones I didnt clean. They are a little hard to get it, but I am gonna pull them apart now, and the squit the old deoxit in there...let em dry a little and stick them back together. And as soon as possible I am going to check FSM for the tests I can do from ECU to those injectors.

    Quote Originally Posted by Jetaway View Post
    You shouldn't think just in terms of the absolute measure -- .001 or .002, but in terms of percent. Your intakes are 1/8th or 12.5% tight and the exhaust somewhere between 20% and 25% loose.

    Bit more ominous, isn't it? Chris
    Yes that is a good point, it does point out the problem a little more when I think of it that way, But I will still need to warm up car and check the clearances when warm. Just so I know where they are at warm, and cold too.
    Last edited by argniest; 04-19-2011 at 11:56 PM.

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    Yeah, I was thinking about the banking too. It would be "too easy" if it were 1 entire bank. Then you'd almost know where the problem is (that one wire from the ECU feeding the one bank). However, I suspect it's an accumulation of bad connections.

    It's a happy coincidence that you're running off of the front half of your engine, because that leaves you with a detonation every other cycle, resulting in a relatively smooth running condition -- at least smoother than any of the alternatives. (The firing order is 153624, as I recall.) Funny, that!
    My last three sports cars while I still owned all three:

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    noob valve adjusting on 1978 280z-brakebooster.jpg
    If you click that picture, you will see a red line, of where I deteched the brake booster line, from that nozzle. And then I plugged up the nozzle with a short hose and a big bolt in the end of it.

    Quote Originally Posted by FastWoman View Post
    Yeah, I was thinking about the banking too. It would be "too easy" if it were 1 entire bank. Then you'd almost know where the problem is (that one wire from the ECU feeding the one bank). However, I suspect it's an accumulation of bad connections.

    It's a happy coincidence that you're running off of the front half of your engine, because that leaves you with a detonation every other cycle, resulting in a relatively smooth running condition -- at least smoother than any of the alternatives. (The firing order is 153624, as I recall.) Funny, that!
    ohhh wow, thats a great observation....that would explain what another online friend of mine was saying. He was like, man if it was only running on 3 cylinders, SOMEONE would notice. Yeah I NOTICE, its getting 7 to 8 mpg ....but seriously he thought wouldnt a local mechanic notice. Well according to what you just said, maybe not. Because the engine wouldnt sound all that bad. THANKS FOR THAT. I think it just contribute more to my thinking that it has to be electrical problems on the FI side. I mean the plugs 6,5,4 are bad news, and probably black because they are lean not rich. And 6 is nada, a zero, not even doing anything. And then the bad gas milage well, the car is only using 3 cylinders to push itself down the road. I mean whats gonna happen??? suck down gas! And then how the FI connectors just have no effect (except #4 for a brief second) when removing and reinstalling on posts.

    Oh well. I just need time to tackle all these things one by one.

    ieeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

    IF this is true, and I am only running off basically 3 cylinders....my gosh whats it gonna feel like when all 6 are working? in my dreams maybe ....I will be flying....I never had a 280Z that worked normally. Been a long long long fight to get here today. But it does seem like maybe there is light at the end of the tunnel. DARE I DREAM? we are narrowing this problem down?
    Last edited by argniest; 04-20-2011 at 12:00 AM.

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    How in the heck does one go about testing the resistance on the dropping resistors? I removed it from the firewall tonight and see there is very little give in the 4 pin and 6 pin connections. I dont think there is anyway to turn them around to easily stick the multimeter probes down in there onto the pins. The 4 pin for cyl #5 and #6 seems doable since I only have to basically check two things in there. But the 6 pin....man I dont know. I definately want to see what kind of readings I am getting from those, according to what the FSM says.

    I sprayed some deoxit in both of them, but again, with the 6 pin connector dont know how much really got down in there, because I have to turn can upside down and it doesnt like to spray much in there in that upside down situation. I used a mechanics mirror to look inside of the connector, and it seems like some deoxit got all over in there. BUt I cant say for sure how much. But it did look like each compartment in the connector was wet with dexoit.

    I dont know about pulling and of the connectors off their terminals either. Normally, if the plug was accessible, I would have just done it and moved on. But these things are in a very difficult place to do much with, and the clutch cylinder is in the way too. That is not helping at all.


    Thanks
    Last edited by argniest; 04-20-2011 at 12:19 PM.

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    Just measure it with a digital multimeter -- cheap, available at your local radio shack or auto parts store.
    My last three sports cars while I still owned all three:

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    i put a schematic drawing in your other post. There are two resistor blocks. Please note that injectors 1,2,3,4 are on one of the resistor blocks and 5&6 are on the other block.
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    Sorry what I meant, was they are in a very difficult to get at place in the car. I have the digital multimeter and wiring diagrams for the car (laminated and colored). Its just that I cant seem to position the 6 pin connector to where it will be accessible to test it very easily at all. I am being very careful with the connectors. If I messed them up,,,,,bad news!

    And yup, I have the schematic and troubleshooting pages also from the FSM. So I will test the 4 pin in a few minutes, but I dont know if I can position the probes to get a measurement on the 6 pin connector. Someone else said I could take measurements back at the ECU for the dropping resistors? but how to do that? I was just hoping to measure them at the source of the 4 pin and 6 pin connectors

    Thanks!@!

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    Dig in to the FSM a little deeper. There is a section on testing at the ECU plug and a section on testing the dropping resistor and injection circuit at the plug.
    Last edited by Zed Head; 04-20-2011 at 05:59 PM.

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    OK I got the Dropping resistors disconnected. My z parts person told me they are not so sensitive. Just pull the plugs out of there. That was too easy, Im just very careful with everything. Use kid gloves. I just didnt know they came apart like that NOW I DO. SO I measured the resistance of each of the pin combinations as suggested in FSM. They all read 6.2 ohms of resistance. So I believe that is within their specs.

    Next I looked at the FI bible and they showed nice diagrams of which pin number on the dropping resistor connectoins are related to which fuel injector lead. So then I ohm'd them out (like pin 37 to pin 37 for injector #1). To make sure no broken wires. Each of the 6 wires going from one side of each of the fuel injectors, back to the two seperate dropping resistors (4 and 6 pin connectors) showed 0.001 or 0.002 ohms. Which tells me there is a good path from the Dropping resistors to the fuel injectors. Next I am gonna take the big brute ECU connection off (after disconnection power while I do it) and then hook power back to battery, and then start checking the other fuel injector connectoins in the FI bible. Also they show 4 different grounding connections to check. So I am on a roll I will check those too.

    SO at least we know there isnt a problem with the dropping resistors, and no problem with wiring going from the two dropping resistor connectors to the one side of injectors. Hey its a start

    No smoking gun there. crud. Still wondering how 6,5,4 injectors connections can be pulled off at low idle and high idle speeds with no effect on engine performance. WT!!!
    Last edited by argniest; 04-20-2011 at 09:11 PM.

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    ELECTRICAL TESTING RESULTS
    OK so I ran electrical connection tests on various things tonight. After removing the dropping resistors, I was able to clean both sides of the connection with deoxit. They actually looked pretty good anyway, but since I needed to test them. Figured I would just clean them while I could. After cleaning them and testing them I reinstalled them back as they were supposed to be.

    DROPPING RESISTOR CONNECTIONS
    I referenced the FSM and it showed that between all the various connections
    on the 4 pin and 6 pin connections I should get 6 ohms.

    Well I got 6.2 on all of them. I will assume that is OK, right?

    Also, I referenced the electrical diagrams in FI bible to figure out how to do a continuity check on the wires going from the two connectors for Dropping Resistors to the matching pin number on the fuel injector. All 6 of them tested positive with continuity of like .001 or 002 or 003, but mostly .000/.001.

    So that seems to tell me the wiring is just fine between the 4 pin and 6 pin dropping resistor connection and the one side of the fuel injectors. The battery was disconnected during all the above tests.

    MY GROUNDING POINT
    I always used the same ground for all tests that required a ground. I stuck the (-) black probe on a small screw in the doorway at the bottom that holds that black plate on there.


    BATTERY VOLTAGE
    My battery, when measured at the battery itself was 12.34v and the also, voltmeter gave it a green light.

    FI BIBLE TESTING PROCEDURES
    Then I went through most of the FI bible and ran all the tests that I understood.
    Here is results. The battery was connected, but car was off for these tests.

    TEST #1 - (3a) AIR FLOW METER - RESISTANCE #1 ----> 0.206K (Manual says approx 180 ohms)
    TEST #1 - (3b) AIR FLOW METER - RESISTANCE #2 ----> 0.203K (Manual says continuity plus small resistence)
    TEST #1 - (3c) AIR FLOW METER - RESISTANCE #3 ----> 115 ohms (Manual says approx 100 ohms)

    TEST #1 - (4) AIR TEMPERATURE SENSOR - RESISTANCE ----> 2.81K (Manual says 2250-2750 ohms for 68 degrees)
    I dont know exact temperature of coolant. But it was maybe 60 to 65 in the garage tonight. I had heater on for a while.

    TEST #1 - (5) AIR FLOW METER FUEL PUMP CONTACTS ----> I dont have a pin #20 in my ECU connector
    TEST #1 - (6) WATER TEMPERATURE SENSOR ---> 2.98K (manual says 2250-2750 for coolant temp of 68 degrees
    TEST #1 - (7) FUEL PUMP RELAY CIRCUIT ----> I dont have a pin #20 in my ECU connector


    PROBLEM????
    TEST #1 - (8) AIR REGULATOR AND FUEL PUMP CIRCUIT----> 61.3 (tested several times)
    this is just supposed to be continuity


    TEST #1 - (9a) CONTROL UNIT GROUND CIRCUIT 1 ----> OK CONTINUITY 0.00
    TEST #1 - (9b) CONTROL UNIT GROUND CIRCUIT 2 ----> OK CONTINUITY 0.00
    TEST #1 - (9c) CONTROL UNIT GROUND CIRCUIT 3 ----> OK CONTINUITY 0.00
    TEST #1 - (9d) CONTROL UNIT GROUND CIRCUIT 4 ----> OK CONTINUITY 0.00

    TEST #2 - (1) IGNITION COIL TRIGGER INPUT CIRCUIT ----> 11.5 volts
    TEST #2 - (2) CONTROL UNIT POWER INPUT CIRCUIT ----> 11.91 volts

    IGNITION ON DURING THESE TESTS, BATTERY CONNECTED
    TEST #2 - (3a) #4 INJECTOR CIRCUIT ---> 10.50 volts
    TEST #2 - (3b) #1 INJECTOR CIRCUIT ---> 10.48 volts
    TEST #2 - (3c) #5 INJECTOR CIRCUIT ---> 10.48 volts
    TEST #2 - (3d) #6 INJECTOR CIRCUIT ---> 10.48 volts
    TEST #2 - (3e) #3 INJECTOR CIRCUIT ---> 10.47 volts
    TEST #2 - (3f) #2 INJECTOR CIRCUIT ---> 10.48 volts

    I dont know if that is normal or not???? why it would not be 12.xx volts.

    Thats all the tests I did, there was like maybe 5 other ones I didnt do.
    Its too late and I dont want to mess with anything else. LIghts are going out upstairs.... X=X

    EDIT: TESTS I DIDNT DO YET FROM FI BIBLE
    TEST #1 - (1) IDLE THROTTLE SWITCH Page 47
    I dont know how I can do this test. how can I probe the ports if the car needs to be running, which would imply that the ECU harness is connected, thereby negating my ability to stick a multimeter probe into ECU connector pins

    TEST #1 - (2) FULL THROTTLE SWITCH Page 48
    Same issue as previous, I dont understand how I am supposed to do this test

    TEST #3 - (1) "START" SIGNAL CIRCUIT
    I need to do this when I am awake. Didnt feel like doing this at 2am
    But I think I know what to do here

    TEST #3 - (2) AIR REGULATOR CIRCUIT
    I need to do this when I am awake. Didnt feel like doing this at 2am
    But I think I know what to do here

    TEST #3 - (3) COLD START SYSTEM CIRCUIT
    ummmm...I dont know about this....hmmmmm
    I think its basically similar to previous tests

    My gosh thats it.
    Last edited by argniest; 04-21-2011 at 08:03 AM.

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    Great presentation of data!

    ~ 6ohms is normal for dropping resistors

    I can't recall the air regulator and fuel pump circuit test details. If the schematic shows this going through relay then the 61.3 ohms is probably carbon on the relay contacts or a corroded connector in the circuit somewhere.

    The injector test of 12.5 Volts is not measuring battery voltage. It is measuring the voltage at the ECU which will be applied to the injector harness. The resistance between the battery and and connectors and circuitry within the ECU upstream from your measuring point is causing the drop.

    btw a fully charged battery (measured with no load) is ~12.8V and fully depleted is ~ 12.0V (Measure after the battery is "settled" and has not just come from being charged by the alternator (during a ride or idling) or after it was just under load.... first thing in the morning is a good time)... btw battery V sould not be an issue with your problem... seems like bad connectors or bad injectors.
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    Great presentation of data!

    ~ 6ohms is normal for dropping resistors

    I can't recall the air regulator and fuel pump circuit test details. If the schematic shows this going through relay then the 61.3 ohms is probably carbon on the relay contacts or a corroded connector in the circuit somewhere.

    The injector test of 12.5 Volts is not measuring battery voltage. It is measuring the voltage at the ECU which will be applied to the injector harness. The resistance between the battery and and connectors and circuitry within the ECU upstream from your measuring point is causing the drop.

    btw a fully charged battery (measured with no load) is ~12.8V and fully depleted is ~ 12.0V (Measure after the battery is "settled" and has not just come from being charged by the alternator (during a ride or idling) or after it was just under load.... first thing in the morning is a good time)... btw battery V sould not be an issue with your problem... seems like bad connectors or bad injectors.
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
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    The car hasnt been started for a few days now...since I have been running all these tests. So that should meet your criteria about the battery. It seems to me that since the dropping resistors are going to drop the volatage to 3 volts or whatever it is the FI's need, that it doesnt matter that I am getting 10.5v on each of the FI circuits? As long as it supplies more than 3 volts, it would just be dropped down anyway. Or are you saying it does matter?

    I think it is interesting, that using the same grounding point, would show different voltages for the different circuits like 11.91, 11.5, and all the ~10.5's. I dont know if that would be typical or not. But when it says everything should read battery voltage which is 12.34 in my car and none of my voltage numbers are reading that. Just dont how critical this voltage information is or not.

    I realize there are different lengths of wire, different connections paths, different amounts of corrosion, resistance, etc. :-) that could be causing the voltage differences. Remember though, I have done a lot of cleaning of sensors and connections all through out the engine compartment (havent really cleaned much inside car except fuse box, and replaced all fuses)

    I will wait and see what others think about this data. BTW, I doublechecked everything too, same results.

    QUESTION: Should I clean the ECU 35 pin connector with deoxit while I have it disconnected? It actually looks clean to me. but who knows for sure exactly how clean it is.
    Last edited by argniest; 04-21-2011 at 10:55 AM.

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    Argneist, I've got a bit on my plate this evening, but I'll research these things later. I'm pretty sure the voltages you show ARE battery voltages, not voltages from the ECU. (The ECU is unplugged, right?) It's been a while since I've run these tests and looked at the schematics. What is your battery voltage, BTW?

    The air regulator resistance is about right. It has a heater coil inside it that heats the bimetal coil that closes down the air flow.

    I'd be interested in a few measurements that might or might not be in the EFI Bible. Anyway, later... Meanwhile, I have to buy lumber and nails for some work tomorrow.
    My last three sports cars while I still owned all three:

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    Oh, and didn't see your last post.

    Yes, clean any connectors...

    I shall return!
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    Quote Originally Posted by FastWoman View Post
    Argneist, I've got a bit on my plate this evening, but I'll research these things later. I'm pretty sure the voltages you show ARE battery voltages, not voltages from the ECU. (The ECU is unplugged, right?) It's been a while since I've run these tests and looked at the schematics. What is your battery voltage, BTW?

    The air regulator resistance is about right. It has a heater coil inside it that heats the bimetal coil that closes down the air flow.

    I'd be interested in a few measurements that might or might not be in the EFI Bible. Anyway, later... Meanwhile, I have to buy lumber and nails for some work tomorrow.
    Let me know if you want me to test anything else. For now, I am hooking ECU back up (Yes it was totally unplugged)
    And I am about to use a noid light, and spark plug tester to evaluate the spark and injector, one by one, and compare to each other

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    Then I am going to use propane into the intake back by number 6,5,4, and see what effect it has. Im a little despodant that the wiring is all appearing to be OK. No smoking gun there, yet.

    UPDATE, I THINK I FOUND A PROBLEM HOUSTON
    Well so tonight I hooked up the noid light to each injector, and it flashed on all of them. Seemed about the same intensity, if that mattered.

    Now I hooked up several spark plug testers...but the one that has a little clamp on it, and you can see the color of the spark, the size of the spark, and if it goes dark (a miss?). Well that is exactly what I saw happening in several of the plugs. 6 didnt seem to miss, but I only watched it for like maybe 1 minute. 5 seemed to be missing once in a while where the spark just missed a beat or two and disappeared, and 4 definately went dark....I cant be imagining it, I mean it was gone for like 1/4 second or long, and 3 didnt seem to miss, but 2 seems to miss the longest...where the plug was definately dark inside, noticible again, but I cant say exactly for how long. But I am sure in slo-mo, it would seem like a lot longer....since normally that spark was just dancing around and around and around....and then BOOP, BOOP, OUT! GO! THE! LIGHTS!

    I couldnt test 1 because the stupid clamp broke and I just fixed it. Its too late to start it up now, dont wanna piss of my neighbors. So I will test #1 tomorrow.

    But another online friend of mine told me we definately found something, and to replace ignition coil and if that doesnt fix it to replace pickup coil next.

    He really believed that we finally found a smoking gun!!!! real evidence. I told him I was kind of nervous that I was seeing things, but I mean it was dark inside for a small period of time. And he said he has seen that happen many times, and in fact said it could have been why the car even died on me 3 times now....jsut as I was driving down the road...and poof engine stops, electricity was still there. And each time it restarted...it was kinda hard starting, but that could be other issues.

    SOOOOOOOOO I am ordering those parts and/or just a refurb dizzy tomorrow. And then I will retest, and if I dont see that problem any more....I am going on one heck of a test drive.

    I mean all these tests are showing good results, nothing wrong, until tonight. YEAH! I hope this is it! At least to solve a major problem...I know I still have to adjust valves...I will I will I promise. :-)
    Last edited by argniest; 04-21-2011 at 09:48 PM.

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    If you do not adjust your valves, you shall be punished! Punished I say!
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    IM GONNA IM GONNA!!!!! REALLY IM 'GONNA' ADJUST ME VALVES

    But I am also going to replace ignition coil and pickup coil. And on my lunch break, I am going to confirm the missing problem again, by watching the sparks fly. I am sure I will see the same things.

    OK: Tested again, I definately see lapses of when the spark is firing. In fact on #4 and #5 (the plugs that were the black carbon looking) it almost looks like half the time they are sparking and the other half the time they are dark. Number 1 and 6 looked like they missed spark a few times, and 2 and 3 were missing spark several times too. 2 wasnt as bad as 4 and 5, but definately goes dark, without any spark!!!!! for a brief time within a matter of 10 or 15 seconds, its going dark (no spark) several times.

    SMOKING GUN! =======> IGNITION COIL AND/OR PICKUP COIL?
    Last edited by argniest; 04-22-2011 at 01:35 PM.

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    I think it was recommended to check the distributor cap and rotor. Easy to do and very inexpensive to replace.

    A bad coil would affect all sparks. A bad disturber cap would affect specific ones.

    FYI adjusting valves is a heck of a lot easier than all of the stuff you have done troubleshooting... I hope that gives you confidence
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    Also check where plug wires connect to distributor cap.

    You can also measure FI flow: get 6 small glasses of same type, pull FI rail and place glasses under each injector. Crank the car to fill them up. After a certain amount of time you will see if you have even flow by the amount in the glasses... keep sparks away.
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    Yes, Argneist, you will be punished! Adjust the valves! Grrrrrrr!

    That said, I think you'll see marked improvement when you straighten out your ignition. Your motor might not end up 100% right (or might), but I think you will see MAJOR improvement.

    This is what I'd replace, even without testing:

    Spark plugs (NGK B6ES-11)

    Plug wires if they're older than say 5 yr. or if you don't know their age. Use the NGK spiral wound silicone insulated wires, similar to the ones you have.

    Cap

    Rotor

    Once you've replaced all of these, try starting your engine and see how it idles. Readjust your idle speed if necessary. Check your engine vacuum. Listen to the exhaust. The exhaust puffs should be perfectly spaced. There should be nothing random about them. Put your timing light on the wire between your ignition coil and the center post of your distributor. There should be no missing flashes. Then check back with us. You might have other ignition components that need replacement, but the above should be replaced irregardless.

    Oh, and I think you've ruled out problems with the electrical firing of the injectors with your noid lights. That doesn't mean the injectors are necessarily in the clear, though. Your 4-6 injectors might be clogged or stuck. But for now, the smoking gun seems to be elsewhere.

    Good job, BTW! Well done!
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    I hear ya, I have gone through a lot, and I dont regret anything I have done to the car. I wanted to replace as many old parts as I could. WHen I saw the 1/2" of rust in the tank, well, now evrything that touched fuel is brand new. I have reviewed processs to adjust valves and will be doing that as soon as possible. ALl the noid light tests were fine, the ECU tests in the FI bible were all normal. NOw today I learned that the 1978 has some kind of EI Control module???? I dont remember seeing that anywhere,except when I was looking at a parts list from motor sport auto. Can anyone tell me about that, and could that be causing my spark issues?


    UPDATE: I did another test
    (using a new spark plug tester, the kind you actually see and hear the spark, which is the same as the other one). SO to rule out bad equipment and therefore bad results, I tested a third time. And now that I know what I am looking for, let me say this. I revved up engine while plug tester was on each wire, and WOW sometimes the SPARK WAS GONE for like 2 seconds at a time. When I relased throttle, the spark came back, but still was missing, then sparking, then missing etc

    #1 and #6 were not nearly as bad as others, but I did see and hear them missing. #2 was pretty bad, it would miss for like 1/4 to a 1/2 second at a time, and multiple times in a row. #3 was pretty bad too, not as bad as 2. And 4 and 5 (their spark plugs were the ones that were black and dryish looking) were missing for like 1 to 2 seconds. I am saying, there was no visible spark at all for like 2 seconds, and then it would come back for a few, then go away, etc. And revved up engine each time I tested another plug, and sure enough it would still be missing spark.

    So does this likely mean I should replace ignition coil first and then recheck.

    NOW THE QUESTION IS THIS, do you think I can buy an ignition coil locally for my 1978? Or will I have to get it from the blackdragon, motorsport, etc or my Z guy from the NW of course.

    Because it would be nice if I coud go get it right now, and slap it in there. Im dying to try this ASAP! and recheck....it may not solve all problems (I know I know valves) but could solve most of them!!!

    BUt maybe its bad karma to put some hack cheapo piece on there???? I normally buy only the good stuff.

    ALso, do you think I can get a decent cap and rotor locally. NOrmally I order all parts online, except my plugs. But now I am dying to try all these suggested things....plugs (have new lready), NGK wires...can you send me a link to which ones you mean, rotor, distrib cap, and ignition coil

    MY INJECTORS: I am hoping they are fine. SInce they are brand new and good quality, and I was very careful when installing them and handling them...so it was yet another first time doing something like this, of course now, it seems realativly trivial to do it again, as most other things I have done now.
    Last edited by argniest; 04-22-2011 at 04:04 PM.

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    I have an MSD Blaster 2 coil on my system. Nice coil, but I don't see it listed at AZ. I see a Blaster 3 coil for $47, but I'm unfamiliar with the Blaster 3. I'm guessing it's an improved version of the Blaster 2? Mine is a bit smaller than the OEM coil. I had to put a wrap of rubber innertube around the coil to mount it in the OEM bracket. You can also buy an MSD brand bracket. You should be able to find these at your local parts store.

    I think you have to order NGK wires. I haven't found them locally in my area. Here's an auction for a set on Ebay:
    http://cgi.ebay.com/ebaymotors/NGK-8...Q5fAccessories

    Advance Auto parts in my area carries the NGK plugs.

    I would think any cap and rotor would be fine -- available at an auto parts store of your choice.

    Your local parts store might not have all items in stock, but it would probably take no more than 1 day to get them in from a nearby warehouse.

    Keep in mind there is still one item in your system that could be bad -- your ignition module. Try the rest, and see how your car runs. If you still have ignition problems, then consider either a replacement OEM ignition module or a GM HEI retrofit.
    Last edited by FastWoman; 04-22-2011 at 04:14 PM.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Quote Originally Posted by FastWoman View Post
    I have an MSD Blaster 2 coil on my system. Nice coil, but I don't see it listed at AZ. I see a Blaster 3 coil for $47, but I'm unfamiliar with the Blaster 3. I'm guessing it's an improved version of the Blaster 2? Mine is a bit smaller than the OEM coil. I had to put a wrap of rubber innertube around the coil to mount it in the OEM bracket. You can also buy an MSD brand bracket. You should be able to find these at your local parts store.

    I think you have to order NGK wires. I haven't found them locally in my area. Here's an auction for a set on Ebay:
    http://cgi.ebay.com/ebaymotors/NGK-8...Q5fAccessories

    I would think any cap and rotor would be fine -- available at an auto parts store of your choice. Your local parts store might not have all items in stock, but it would probably take no more than 1 day to get them in from a nearby warehouse.

    Keep in mind there is still one item in your system that could be bad -- your ignition module. Try the rest, and see how your car runs. If you still have ignition problems, then consider either a replacement OEM ignition module or a GM HEI retrofit.
    Is the ignition modle aka the transistor ignition unit. If so, I was unaware of its existince for the most part until recently. I hope thats not bad. But as you said, I WILL be trying the other stuff first. Mainly I want to make sure I get a compatible ignition unit.

    UPDATE AGAIN: OK, I called a local Advacend Auto and by tomorrow morning they can have a borg-warner ignition coil, cap, rotor, and ignition pickup.

    And I didnt even have to leave my desk or pay 1 cent to order them Nice!

    But is borg-warner stuff going to be OK on my Z car? I hope so....otherwise its gonna be another week before my normal Z car parts supplier can get all this stuff to me.


    If its OK to use this stuff, that means tomorrow morning I could, for the first time in a long time, have a very well running Z car!!
    Last edited by argniest; 04-22-2011 at 05:25 PM.

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    When you get your car sorted out, you should upgrade to a 280zx distributor.

    Also with rust in your tank you should install a filter before your fuel pump.

    When you feel brave, acid wash and sealing your tank is a fun thing to do with POR15 gas tank sealer.
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
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    Quote Originally Posted by Blue View Post
    When you get your car sorted out, you should upgrade to a 280zx distributor.

    Also with rust in your tank you should install a filter before your fuel pump.

    When you feel brave, acid wash and sealing your tank is a fun thing to do with POR15 gas tank sealer.
    I have installed the G3 clear fuel filter between tank and pump. Check.

    I have had the gas tank insides washed, boiled, acid, and sealed 2x by a family member who restores high end cars for a living . Check. It will outlive me for sure. Then I used Eastwood companies 4 step chemical/painting process for the outside. Its better than new now. I had to make sure that was done, before I replaced everything else going all the way to the fuel injectors.

    What is the general procedure and thought process to move up to a 280ZX distributor?
    And is it a direct drop-in?

    Thanks for advice once again.
    Last edited by argniest; 04-22-2011 at 07:44 PM.

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    BTW When you mentioned rust it made me think your #6 injector may be clogged.

    Did this on my 77. Easy and great upgrade: http://atlanticz.ca/zclub/techtips/d...tor/index.html
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
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    Quote Originally Posted by Blue View Post
    BTW When you mentioned rust it made me think your #6 injector may be clogged.

    Did this on my 77. Easy and great upgrade: http://atlanticz.ca/zclub/techtips/d...tor/index.html
    All my injectors are brand new. I installed them after I reinstalled the brand new fuel tank, cleaned out all metal fuel lines, all new fuel hoses, new fuel pump, damper, new G3 fuel filter in back of car, new OEM nissan fuel filter in engine area, cleaned fuel rails, new injector hoses, new injectors. I mean the entire fuel delivery system was brand new, before I let any fuel touch my new injectors. Just lettin ya know.

    The problems all stem from the fact that I have triple checked the spark on the car, and its bad news. All of the spark plug wires showed intermittent spark, and long durations where it just disappeared. I really believe that is the cause of most of my problems....maybe tomorrow I will have it fixed. Im just waiting to hear from you all, if I can use those parts I mentioned above. Or if I should wait until a week or two to get the best parts available. From my Z parts supplier who has been working on them since 1978
    Last edited by argniest; 04-22-2011 at 08:33 PM.

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    Are the parts Borg Warner or BWD? Borg Warner makes power train parts like transmissions. BWD makes electronic parts like those you mentioned. I use BWD and have found that the parts are of good quality, and at least a small step above some suppliers in materials, like brass electrodes over aluminum for the rotor cap. I don't see plug wires on your list, have they already been replaced?

    The ignition module on your car is up under the passenger dash by the fuse box. Your initial symptoms fit ignition module problems to a degree. I had my 1976 module go bad, it started cutting out and misfiring if I went above 3500 to 4000 rpm and would not stop misfiring until I turned the key off and restarted the engine. But the module's don't seem to all fail the same way, they have different symptoms. From what I've read, usually the engine just dies, then will restart after a few minutes, sometimes longer.

    Ignition pickup coils don't seem to go bad that often, you might wait on replacing that part. It would be worth checking the gap on yours though to be sure it's right.

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    The ignition module is common to all plugs and injectors. Your problem is rich on 4&5 and lean on 6. This seems more like injectors.

    However it could even be something weird like obstructions in the fuel rail. Some more checks to do.

    Try getting 6 glasses (all same) then pull rail and have each injector sit in a glass. Crank and fill the glasses to see fuel flow across the 6. Watch out for spark.

    This is an old tip from Wayne Monteath of Ottawa.
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    The person who buys on price alone is this man's lawful prey.


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    Quote Originally Posted by Zed Head View Post
    Are the parts Borg Warner or BWD?.
    OK, in my notes I wrote down BWD, but then the guy at auto store also mentioned Borg Warner. I assumed they were the same. But he did tell me again, BWD was who made all the 4 parts I was asking abut, and that they said they could get my tomorrow morning.

    Quote Originally Posted by Zed Head View Post
    I don't see plug wires on your list, have they already been replaced?
    Well, the NGK blue wires, look pretty new to me, but of course I dont know their history. I bought some universal plugs, but didnt realize I had to cut them to my own length and then I suppose crimp end on. I am taking them back, and will just have to wait a few says for the NGK NE-61's is what I thought the guy told me.

    And yes, I have several sets of new plugs.

    Quote Originally Posted by Zed Head View Post
    The ignition module on your car is up under the passenger dash by the fuse box. Your initial symptoms fit ignition module problems to a degree. I had my 1976 module go bad, it started cutting out and misfiring if I went above 3500 to 4000 rpm and would not stop misfiring until I turned the key off and restarted the engine. But the module's don't seem to all fail the same way, they have different symptoms. From what I've read, usually the engine just dies, then will restart after a few minutes, sometimes longer.
    My car died the other night when I was driving it. ANd it died two times in January, when it was like 9 degrees outside. Didnt know what to think of that, but since they as I said, I have replaced everything in fuel system. So it seems that you had a similar problem with yours dying. I also waited a few minutes, and it always restarted. Of course after past few days, I have learned a lot more. I know how to check fuel inj with noid light, and spark with 3 different kinds of testers,....and various things with my multimeter.


    And yup, I looked in car and manual about the transistor ignition module, now I am learning about that next

    Quote Originally Posted by Zed Head View Post
    Ignition pickup coils don't seem to go bad that often, you might wait on replacing that part. It would be worth checking the gap on yours though to be sure it's right.
    Will it hurt anything if I replace the ignition coil tomorrow morning with this BWD? the thing is, that is a REALLY easy thing for me to do. And some other people are telling me, it could be the ignition coil. If not, pickup coil next. As long as it wont hurt anything, I woud like to replace ignition coil. I mean it should take me like 3 minutes.

    Taking out the DIST and fixing pickup coil NOT easy for me. I have never really even seen them before execpt from the outside. And unti now, havent really known what they do exactly. BUt tonight I have been studying about the dizzy in the z car, and other related components. Its at least making a lot more sense than a few days ago
    Last edited by argniest; 04-22-2011 at 10:00 PM.

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    Blue, good point, I was referring back to what I thought was one of the original problems, car dieing and then waiting to restart, but to be honest, I might have it confused with someone else's problem. argniest is all over the forum! (not a problem, just hard to track the various threads...).

    I think that the thought now is that misfires are causing plug fouling, which looks like rich running. I do agree though, if the injectors come out again, verifying proper flow is worth doing.

    argniest, I think this has been mentioned before (by me, I'm a big FSM fan) - the FSM will give you the same test procedures as the "Bible" but with much more information specific to your car (like how the electronic ignition system works). You'll need it if you replace your magnetic pickup in the distributor, for instance.

    You're on the edge of the old "replace and hope" slippery slope...

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    Quote Originally Posted by Blue View Post
    The ignition module is common to all plugs and injectors. Your problem is rich on 4&5 and lean on 6. This seems more like injectors.
    Well I watched the spark patterns today 3 different times. ANd always numbers 5 and 4 were missing for long periods of time. Im talking up to 2 seconds, and even 1 second miss when revving engine. It seems if the spark was that messed up on 5 and 4, that would explain why the plugs on 5 and 4 were also looking screwy, no? Of course I dont know anything for sure...Im just saying. And also #6 was missing too, just not as bad as 5 and 4.

    Numbers 1, 2, 3 were missing, but not as many times, nor for as long duration as 5 and 4. Number 2 was pretty bad though. I mean I saw all of them missing, but #1 was the most normal looking during all three of my tests.

    And I cant say this for sure, but I also thought that the spark looked dimmer/weaker sometimes. ANd when that happened, I think it was more yellowish than white or blueish, if that makes any sense at all.


    Quote Originally Posted by Blue View Post
    However it could even be something weird like obstructions in the fuel rail. Some more checks to do.
    Welllllllllll I did clean everything thoroughly ...im talking all metal fuel lines, fuel rails, every hose is brand new...etc. New tank, new fuel filters in back and front. I wanted to be sure I had everything spotless before installing new injectors. I do understand why you are saying to do those FI tests....but I am gonna wait a little longer...until I have taken other things out of the equation related to spark issues. Since it looks to be major problems with spark in most of the plug wires. That is hard evidence to me, based on what everyone has been telling me past few days. Including people on here, my Z parts person, and an online mechanic friend who has spent counless hours with me at night to help me change everything, in my quest to renew everything in the car.
    Last edited by argniest; 04-22-2011 at 10:17 PM.

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    Quote Originally Posted by Zed Head View Post
    You're on the edge of the old "replace and hope" slippery slope...
    I know it seems that way, but from day 1 with the car, I told myself, I wanted to renew everything I could with the car. Its just been a long crazy winter, in learning about all this stuff. And doing all this stuff. Everyone has been soooooooooooo helpful with my project. Friends on here, other online mechanic friends, remote family members who I occasionally visit and discuss things about the car - who work on restoring cars or just in the automotive repair, and even a few local mechanics too, etc etc etc

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    Argniest I love your attitude, perseverance, and very clear, concise and well formatted posts! Also your logic and careful approach to tackling problems is superb... keep it up!

    Stick with the NGK plugs and wires and you should have no problems.

    An easy way to check spark is simply to idle the car then pull one plug at a time. You can feel the spark with your hand on the boot and you can notice how far off the plug that you can hold the boot away before the spark won't jump. It should be the same for all plugs.
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    The ignition unit and the coil "just make sparks". The distributor is a router and it directs the sparks from the coil to the appropriate cylinder.

    If you have problems with 5&6 then it makes sense that the components associated with these cylinders would be the culprit. The suspects would be distributor rotor and cap and plug wires.

    If you want to check your plug wires just idle the car in the dark and spray(mist) water on the wires...any problems will be seen as sparks to the valve cover and such (crappy Bosch wires did this within 5 months on my Rav4... DON'T BUY BOSCH WIRES
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
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    Quote Originally Posted by Blue View Post
    Argniest I love your attitude, perseverance, and very clear, concise and well formatted posts! Also your logic and careful approach to tackling problems is superb... keep it up!
    Thanks I really appreciate that comment :-) I use similar skills in my years of designing software, debugging it, and fixing all kinds of problems with software, hardware, firewalls, routers, computers, virus removal etc ITS A step by step, bit by bit approach to limit scope of problems. I know there is a 1000 different ways to go about it. I have gone down my path to Z enlightment, slowly but surely.

    Quote Originally Posted by Blue View Post
    Stick with the NGK plugs and wires and you should have no problems.
    I got NGK plugs, I should have ordered new NGK wires a LONG time ago. I had my finger on the trigger many times, just didnt do. I am sorry now. Because I want new NGK's like right now.

    Quote Originally Posted by Blue View Post
    An easy way to check spark is simply to idle the car then pull one plug at a time. You can feel the spark with your hand on the boot and you can notice how far off the plug that you can hold the boot away before the spark won't jump. It should be the same for all plugs.
    OK, not to sound like a broken record, but I believe the 3 tests I did today, and one last night using those special spark testers, has beyond a shadow of a doubt proved that all my cylinders are not getting spark all the time. Some are much worse off than others. As I mentioned, 5 and 4 are the worst looking spark, missing for several seconds. I mean its like someone just turned them off. ANd then they come back on, and spark some, and then back off....etc 6 also misses sometimes, but doesnt go dark like 5 and 4. ANd well 3 is kinda like 6, but a little worse, and 2 is like worse then 3, but not as bad as 5 and 4. ANd well, 1, doesnt seem to miss very much. But I think I did see it miss a few times.

    So all I am saying is that I dont know if I need to prove anymore that I have a spark problem, right? It seems I have spark problems on all of them, and much more severe on some. Just my 2 cents

    I just wish I knew which part of the system is causing this spark problem, so I could just fix it and move on. If my local store has those 4 parts, I will replace all the easy ones, tomorrow morning, and see if it makes any difference. I will keep hoping it will. ANd I dont have to dig deeper.
    Last edited by argniest; 04-22-2011 at 11:12 PM.

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    My only thought on the spark problem theory causing uneven fuel burning in some cylinders is that the photo you showed of the plugs had 6 lean and 4&5 rich with 123 similar and almost normal.

    If you had a coil or ignition problem then it would affect all cylinders equally as it is upstream from the "distributor" (which evenly distributes the spark). This would affect all cylinders evenly. Since you have problems with 6 5&4 there is asymmetry and variance of the symptoms. This leads me to think if it is a spark problem it has to be distributor, or wires. However, it could even be an obstruction in the fuel rail on 6 and a common partial obstruction on 123 (but this is uncommon).

    EFI flow would be another area to confirm. Bad injectors are not uncommon.

    It could also be oil getting into 4&5 cylinders that blackens the plugs rather than fuel.

    Still a lot of possibilities.
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    Well because those parts were readily available this morning, I changed them. I used the BWD cap rotor and ignition coil. NO DIFFERENCE. The spark problems, misfires, seem to actually be worse. I mean longer delays when spark diappears to when it comes back, when I had all 3 of those new parts on there. SO I one by one, tried each of them. ANd the spark problems I have described all remain.

    I will have new NGK wires in a few days. Still wondering about the distributor and that transistor ignition unit. I dont have an osicilliscope so I cant test it that way according to the FSM

    I also retested using two different kinds of spark testers. It really seems like all 6 of them are having spark issues. The more I watch them. I used a tester that you lay on the wire, and it lights up orange. Well it was coming in and going out too. So that to me validates that all 6 are having spark issues, for whatever the true reason is. Of course, during those tests I left the new ignition coil on there. Just to see.
    Last edited by argniest; 04-23-2011 at 02:01 PM.

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    Blue, I agree with you that there could be a fuel delivery/metering issue, but there's definitely also an ignition problem. That's the first thing to correct. Once the engine is firing on all 6, we'll be able to determine more. I'm somewhat surprised that 6 is getting spark and power to the injector, because the plug looks like there hasn't been any fire in the cylinder. I also suspect 4 and 5 COULD appear sooty from extremely lean running. Although it's a counterintuitive interpretation, an extremely lean can lead to a slow and incomplete burn, thus generating lots of unburnt hydrocarbons. I only know this because my own engine was running extremely lean and had similarly appearing plugs. Imagine how confusing that was!

    Anyway, I'm anxious to see what happens when the ignition is straigtened out. I don't think that will be the end of the problems, but I think Argneist will achieve a quantum leap in engine performance. I think once the engine fires on all 6, then a 100-200 mi drive is in order to give a new set of plugs a read. Then if the plugs aren't consistent with each other, it's probably time to pull the fuel rail again (sorry, Argneist!) and spray some fuel into 6 juice glasses.

    BTW, Argneist, the plug read will be a lot more meaningful if you ADJUST YOUR VALVES! You can do that while waiting for ignition parts to come in!
    Last edited by FastWoman; 04-23-2011 at 09:07 PM.
    My last three sports cars while I still owned all three:

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    I have a little new information to report today. According to another friend of mine, I was using the spark plug tester for newer cars and not a standard one for something like the Z car. I guess if I think about it, that makes sense. I mean if you walk into a car parts store they are going to have components for recent cars, not something that is 3 or 4 generations old.

    What I was told is that I need something for standard ignition systems, not a spark tester for high output ignition systems. On the tester itself I mainly used, it said HEI. Which supposedly means for higher output systems. The interesting thing is that the HEI one that I am using, looks very similar to the one below...except the one below has a metal post in the middle of it...kinda of like a spark plug.

    This is what I was told to get
    http://www.denlorstools.com/home/dt1...ywords=kd+2757

    I guess the one I was using was made for modern cars, and has a larger (air gap) for the spark to jump across, which therefore could be the reason I was seeing such craziness when testing the Z car with the modern tester, when I need a tester for standard ignition.

    Oh well, I am going to get this one, and retest. Since right now, I have the entire EGR system blocked off (one of my tests for eliminating vacuum problems), and the new ignition coil in there, and also the vacuum lines for HVAC system are disconnected. I decided to take car for drive. It still is hesitating. I think I am starting to learn what it feels like to have the car missing.

    Even tho I was using the wrong spark tester, I am starting to believe what I am feeling in the engine is in fact misses in the spark, and there for causing inconsistent accelaration. SO even tho the spark tester I used may not have given completely accurate results, I still think I have a spark problem.

    Once I get the new tester, and new pickup coil next week, and new NGK plugs next week, and also am doing some other tests with distributor....I should have more information to post.

    Thanks again to everyone for helping me. Unfortunately the new ignition coil hasnt seem to make much difference, nor did the new rotor or dist cap. But I just need to learn to change one thing at a time. And retest.

    And oh yeah I am also trying to get my hands on a transistor ignition unit to replace mine. It could be a week or more I suppose before I have that. And I got a loaner ECU from a friend, so if needed I can always try that too. have lots of things inbound in the next week or 10 days. Then will have lots more parts and testing to do.

    PS
    My cousin who restores cars, agreed to help me get started on valve adjust. I just need to take a day off work and go up there to see him. I mainly just asked if he can show me the first one, and watch me do the rest. He wants to do it cold tho. I didnt want to get into a long discussion with him. He works on very high end cars for 30+ years. I have seen cars worth 500,000$ and more at his shop. He does nationwide work. So if he says he wants to do them cold....welllllllllllll how can a noob like me argue. but I am going to bring 1 page of notes from everyone who has told me to do them hot. And see what he says. But regardless, I hope to get this done also within the next week.
    Last edited by argniest; 04-23-2011 at 10:34 PM.

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    OK, so since last posting I got to meet with my relative Steve who restores cars (mercedes, jag's, bmw's) for a living for 30 years now professionally in his own business, he has customers from all over the nation too. He is VERY good! I am very lucky to have him available when I get into over my head.

    Well anyway, I told him what has been done to the car since he saw it last october. He said its good I have eliminated some possible problems. I also re-ran spark tests with two different kinds of testers. And this time the spark looked fine. No misses that I could see. The spark for all 6 was consistent at idle and revving. Those other testers DEFINATELY were not for a Z kind of a car.

    Steve also confirmed good spark the old fashioned way. He pulled wires off one by one and left them a little off the top of the plug...we could hear them all buzzing, and he said sometimes when you do that, because it produces a more powerful spark, that it can light up the cylinders again. but it had no effect. But he did say he really felt the spark sounded good, and of course I mentioned again about both my rounds of testing.

    I spent 2.5 hours with him, and we talked about a lot of stuff, he tinkered and tested stuff, based on his hands on approach from working with cars for like 45 years now, since he was a teenager. Next weekend I am going back and this time he is going to hook up his computer and oscilliscope and ...he says, many many times that computer has shown him problems to fix. So we are both hopeful he will find something. He talked on and on about some possible problems that are causing my 6,5,4 to basically not be working. Things like a problem with the head gasket and it letting air pass between the fire ring, and other issues with valves not closing, cam timing...but of course he doesnt know for sure yet, without digging into things further. He is trying to help me do everything I can to avoid cracking the engine open. He knows that is THE last resort.

    He was kind of surprised, when I told him to pull off 6,5,4 injectors and spark plugs...and then he saw what I meant!!!!!!!!!! He was like what THE???? There is NO difference in how the engine runs. but as soon as he did that on 1,2,3 it was immediately noticable both by removing plug wire and fuel injector connector.

    He also squirted carb cleaner all over, and NO difference anywhere. I have temporarily blocked off the egr system, also removed vacuum lines from hvac system(and plugged them off of course) to eliminate any possible vacuum degradation from those systems. He thought that was good idea to do those things to remove other possible vacuum problems.

    I told him how I removed brake booster line too, capped it off, and NO difference in engine running sounds. He really felt after all that, and the smoke test I had done, etc etc that we really are not looking at an intake/vacuum leak anywhere.

    He also pulled the little vacuum hose that I had plugging off the small nozzle that normally feeds the hvac system...and squirted carb cleaner into intake runners which is down by 6, 5 and 4. NO difference!!! Number 6,5,4 was like they were dead. They didnt care we shot carb cleaner in there. Now that realllllly surprised me, I thought for sure when he did that the engine should have picked up even a little. But nope, the lights are on but nobody's home.

    So lets review some things we know, and what Steve confirmed....noid lights are lighting on all 6, using screwdriver or stethescope you can hear all injectors clicking, spark really seems good form numerous tests on all 6, no missing noticed, fuel pressure is 32 at idle, I ran all those EFI bible ECU tests, and dropping resistor tests...all came back good. I mean I can list other stuff too. But it really seems like we have good spark, and fuel injectors seem to be working, and its using a LOT of gas...8mpg now :-( which makes me believe all 6 injectors are in fact squirting gas. Of course driving down the road on 3 cylinders would also cut gas mileage down drastically.

    Steve has a way to test fuel injectors, its a system he devised himself. So we both agreed, at some point, we will need to verify they are all working. And I also gonna give him my old ones...and see what they look like.

    I could go on an on....we talked for 2 and a half hours about a lot of stuff. He also told me that the valve clearances I reported would not be causing this kind of a problem. I do believe him, seeing as how many cars he has worked on for 45 years. Including some Z's back in the day. He will help me with the valves soon, but first some of these other things.

    First, I want to have him run his computer diagnostics on the ignition system, and lots of other things he said he can tell by that. He agreed its not a bad idea to do that next. Because if there ARE certain problems with it, it could totally hose us over. Like what we are seeing. I REALLLLLLLLLLLLLLLLLY hope he sees something.

    I will also be putting in a different ECU that a friend of mine lent me...and see if that has any effect. If not, I will put the old one back in. Then I have a replacement Transistor Iginition unit sitting here...to try right after that. And a new rotor and cap that are the "good stuff", best quality parts. I will try those following the ECU and TIU. And I have a new pickup coil to put on there too, but Steve will have to help me with that. He was talking over my head about what he was gonna do with the distributor. But basically taking it out, inspecting it, cleaning it, tightening things up??? is what I think he meant.

    He did say the distributor seemed a little loose, and something about how the rotor was turning or moving when it shouldnt be. So that is something he wants to look into more detail next weekend. Im not messing with that distributor, I am going to let him do it. I want a pro to do some of this stuff. I just think its wise to use Steve when I feel the need.

    Oh well... sorry for a lot of rambling. Its just a hodge podge of information. Steve is my ace in the pocket. I really look forward to next weekend. At a minimum he will evaluate the ignition system with his computers and we will have a final proof one way or the other about a lot of things related to that, and hopefully we will replace pickup coil, and he is going to help me put on the new FI connectors, since the current ones barely even stay on there. He wanted to do that soon. If I get lucky, we will do the valve adjustment too. but I think that may have to wait until the next weekend, since he didnt feel it was part of the main problem here. I only want to attack the problems that seem mostly likely to be causing this problem. So he agreed that could wait just a little longer.

    So between me swapping out those important components this weekend, and what we will do next weekend, I think we will know a lot more than now. And will set the stage for the next set of testing.

    I left out more discussions, but I have already bored you to death. You get a cookie if you made it this far :-)
    Last edited by argniest; 04-29-2011 at 11:23 PM.

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    Yum! Me love cookies! (... Cookie Monster)

    It sounds like you're on the right track. I'm guessing what you'll find is that the 4-6 injectors aren't spraying -- perhaps defective, stuck, or clogged somehow.

    I look forward to hearing back from you about how easy and strangely enjoyable the valve adjustments were. That's my favorite part of the engine.
    My last three sports cars while I still owned all three:

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    Default We have found the problem!!!!!!!!!!!!! Am i dreaming???

    Ok anyone watching. Check out the pictures. I went to see my cousin this weekend who restores cars. We spent hours going over my case history, and then he hooked up some big humongous old Sun computer osicilliscope testing machine on wheels. He checked the primary and second ignition and said it looked good. Although, he could see how #6,5,4 were giving irrational readings. It was cool to watch and learn about those wave forms.

    But basically, I got a thumbs up on the primary and secondary ig systems. Especially after what we found next. I have so much to write but will keep this short.

    I got several new replacement pieces since my last post here, on the car (AND NONE OF THEM HELPED THE SOLVE THE PROBLEM, BUT YOU WILL KNOW WHY IN A MINUTE) So I got good quality YEC parts for cap and rotor, and new igntion module, a known working ECU, and a replacement transistor ignition unit.

    I also have a replacement pickup coil (but now I wont need it), and I have good quality replacement fuel injector connectors from bosch.

    I did more testing with the new spark plug testers, etc etc etc but got NO WHERE with that. Planned a drive to see my cosuin yesterday, and boy oy boy did we hit a pot of gold!!!!

    WELL ANYWAY, NONE OF THAT MATTERS. WHAT MATTERS IS NEXT
    So as we talked and looked over stuff, we worked our way around to the EGR system. I had made a gasket to block it off from the rest of the car, to eliminate any possible intake leaks from the whole EGR system. But that didnt help either.

    Well, we took the EGR valve off, and started poking around down there. As you know there two sides to the EGR housing. They are supposed to be separated. WELL GUESS WHAT????? Probably 10 or 15 years ago??? the firewall between those two ports got eaten away. So exhaust has been eating it away for a long long time. And exhaust is pretty acidic anyway.
    Normally the EGR valve is supposed to meter or measure how much exhaust gets moved in there. But a GAPING HOLE!!!!!!!!!!!!! sucking it directly into the intake???? WHOA!

    You will see in the pictures how I stuck a wire right through it. You can see how the white wire runs right over into the intake manifold. That means all that exhaust and air too is going over into the intake manifold to totally screw with 6,5, and 4 cylinders combustion process.

    So that mean I am currently getting a LOT of exhaust/air directly sucked into the 6,5,4, and especially #6, since its closest to it. The more I have tested things, the more I wanted to really believe this was an intake leak/vacuum leak. but no one could find any vacuum leak externally, anywhere on the car.

    However, had I completly understood how this EGR system and the EGR housing underneath were designed, I would have looked there a long time ago. And I could have found this problem. Of course now its seems like a no brainer. Actually, I DID LOOK IN THERE SEVERAL TIMES, but before I didnt comprehend that something like this could be happening.

    We have a plan to band-aid it for this season, because I want my car back to be running good and start driving it a lot more and further way too. And eventually I will be buying a modified throttle body from my Z wizard of the northwest. And fix it permenently.

    I believe immediately after fixing this, a lot of things will happen. Incredible amount more power, smooth idle, normal 18IN of vacuum and not 10-11In like now, normal gas milage, non stinky exhaust, clean burning spark plugs (remember 1,2,3 have been mostly burning OK - and my cousin confirmed he thought my plugs from 1,2,3 were OK).

    I have done so much to this car, it should be like brand new, and even better in some areas because of performance addins like shocks and polyurethene bushings and all new suspension pieces, and you know all the other things that have been done.

    My cousin kept saying he thought it felt like something stupid, but we were both like WHAT!!! WHERE???? Where could this be.

    Well I will post back once he fixes this situation for me. And let you know how it goes. It should be tuesday this week or wednesday if plan goes accordingly.

    ALSO, if you look closely at the picture of the topside of the EGR housing, notice how bad it looks. The hole isnt even round anymore. Its been eating all of that away for who knows how long, and ate a frigging hole RIGHT THRU the firewall between them.
    Attached Thumbnails Attached Thumbnails noob valve adjusting on 1978 280z-egr_and_ecu-006.jpg   noob valve adjusting on 1978 280z-egr_and_ecu-016.jpg   noob valve adjusting on 1978 280z-egr_and_ecu-008.jpg   noob valve adjusting on 1978 280z-egr_and_ecu-017.jpg   noob valve adjusting on 1978 280z-egr_and_ecu-009.jpg  

    noob valve adjusting on 1978 280z-egr_and_ecu-011.jpg   noob valve adjusting on 1978 280z-egr_and_ecu-015.jpg  
    Last edited by argniest; 05-08-2011 at 05:22 PM.

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    eureka! way to go sleuth
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    Definitely great work in digging into the system. It helps to have good diagnostics tools, too.
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    That's for sure a new one. Have to remember this for future people with "low intake vacuum" problems. I wonder how many other corroded EGRs are out there.

    I got curious and just went out to the garage to take apart a 1978 parts intake I have. The EGR channel was totally choked full of caked carbon residue. Interesting that your was the opposite and apparently still letting exhaust gas through, although in excess.

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    Fascinating! Another mystery solved. Great job!

    I just have to say, though...

    YOGURT CUP TEST

    Such an easy thing to do, and it would have revealed your leak. It might have been hell tracing it down, but it would have revealed to you that somewhere in the recesses of the engine... somewhere in that thing... there was a leak. In this case, a leak directly from the exhaust to the intake, bypassing the EGR valve.

    Anyway, you found the problem, and that's what's important. Soon you'll be be taunted no more by the drivers of those VW bugs!
    Last edited by FastWoman; 05-08-2011 at 08:45 PM.
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    aaaaaaaaw goshhhh, exactly about the bugs and minivans. I wont be putting up with that crap anymore hehehehehehe. ! There was nothing I could do before. but now.....ohhhhhhh yeah, watch out. This car, with everything that has been done to it now on my long journey, in some ways, better than almost new.

    I was still gonna do yogurt cup test. During my most likely final and drawn out set of testing everything else that I hadnt done (and maybe retesting a few other things). Thankfully none of that will be needed now!

    I stuck a small led light with a flexible head on it, right down into that EGR housing....and the hole I could see was sort of jagged shaped, but at least size of nickel, and probably in total, the size of a quarter. hows that for a massive intake leak!!!!!!!!!!!!!!!!!!!!! right into the frigging intake and cylinders.

    They no likey likey eating full amounts of exhaust for breakfast lunch and dinner. They will like fuel much better!!!! This explains so much. All the data I have collected can be traced to this problem. I NEVER knew something like that could happen, or I would have been looking for it.

    From now on, in my life, if I ever encounter something like this on other cars I plan to acquire, I will never forget this. It is very rare for something like this to happen from what my cousin says, and another online mechanic friend of mine. I just cant believe there are no other Z people who have seen this happen to their cars. Why o why did I have to be the lucky one. The really good thing in all of this is it forced me to learn soooooooooooooooooooooooooo many things about my Z car. Stuff I dreamed about learning but didnt know if I ever would have time. And now I have good tools, procedures, ideas for future.

    Im very happy on this day. Now I just cannot wait to get it fixed. I am going to try to talk my cousin into fixing it on tuesday. To do the welding of that pipe/(and insert some kind of plugs) and closing it off for good, until I get a new intake and a few months in the winter to carefully take it all apart, put on the new (well good used anyway) intake manifold.

    If I knew how to weld I might fix it myself, but we both agreed taking that pipe off from the exhaust manifold and the EGR housing could be risky. It is possible to break off the back of the intake manifold which would render the car useless until I got a replacement, And then the time to replace it....ughghghghghghgh

    I will let you know how it goes....
    Last edited by argniest; 05-08-2011 at 11:49 PM.

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    It's still odd that only three cylinders were affected by the breakthrough in to the EGR channel. All six intake runners are exposed to the channel so all six should have had excess exhaust gas coming in. The EGR ports in to the runners of your intake manifold might be messed up also. If your band-aid fix is to disable the EGR entirely, you'll probably get back to balanced running, but it might be worth checking the individual EGR ports, if you can get the plugs out. I've never seen one myself so don't really know how much gas they flow.

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    Argneist, I meant that you should have tried my patented yogurt cup test in the first place. You would have found that you were blowing air from your intake directly out the exhaust. That would have told you something weird was going on with the internals of the engine.

    I agree with Zed. There's likely a blockage in your EGR ports somewhere. Maybe disabling the EGR is the path of least resistance. Perhaps you can weld the EGR pipe closed and have a baffle plate on the EGR mount to block off the valve. If you leave the components still mounted (but nonfunctional), then it might not look tampered with, and you'll be able to pass inspection with it. Or maybe you live in a non-inspection state. Dunno.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Here is what the Z jedi master told me to do, just in case someone else runs into this,....they will know what a 30+ year z mechanic would do to fix this. I want it fixed as quickly and easily as possible. So I can drive it finallllllly:

    That's great you found it out. I've seen that happen before and it's not a hard fix to do right on the car. The hard part is diagnosing it as you found out. It's all academic at this point, the diagnosis is sound. As soon as you mentioned something about understanding the EGR system, I knew instantly what the problem is before you described it.

    It's pretty uncommon, but it does happen. I haven't seen it for quite a few years and it didn't even come to mind until now. I've ran across that scenario probably 5 to 10 times in the last 25 years but haven't seen it for the last 5 at least.

    You can cut a section out of the egr tube and weld both ends shut. Then you'll be good to go until you weld the manifold shut.

    DON'T TRY TO TAKE THE TUBE OUT OF THE EXHAUST MANIFOLD UNDER ANY CIRCUMSTANCES OR YOU'LL REGRET IT! They usually won't come out of the exhaust manifold without ruining the tube, and the nut. Then you won't be able to get it to seal on the exhaust manifold. Cut and weld the tube right on the car. Once you cut the tube, then you can take the fitting off of the intake side and weld it on the bench.

    DON'T TRY TO TAKE THE EGR TUBE ADAPTOR OUT OF THE INTAKE MANIFOLD EITHER. Be sure to put a wrench on the adaptor, and another wrench on the nut for the tube and break the nut loose that way. If you try to back out the adaptor, IT WILL EAT THE THREADS!

    I usually take the intake manifolds, and cut the egr section off of it and weld a plate over the end. Then weld the egr tube down by the exhaust manifold closed and it's a done deal.

    For now just do the tube and don't worry about the long term fix. If you ever need to change the head gasket or exhaust manifold, then worry about fixing it permanent. I can modify an intake manifold here and send it to you. Then just send me your old one for the core charge. I'll take your old one and save it for the next guy.

    ****************************
    EDIT: No I live in the middle of nowhere USA, and no emissions to worry about.

    FASTWOMAN: Yes, :-) I was going to do yougurt cup test. I have been going banannas about this...and had too many things I was trying to do. But sooner than later I was gonna do that test, so I would have noticed something was odd. And would have reported it to my guru's.

    IT IS A VERY GOOD IDEA TO DO THAT YOGURT CUP TEST. I even have th yogurt cup sitting right near the car. Im tellin ya I was gonna do it.
    Last edited by argniest; 05-09-2011 at 06:37 PM.

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    I think if I were to name the yogurt cup something else more technical sounding, people might actually be more inclined to do it. Maybe...

    Intake Leakdown Test

    Intake Pressure Retention Test

    Intake Positive Pressure Leak Detection Test

    Translumenal Pressurization Procedure

    I just named it the yogurt cup test because that's what I did it with. I have tons of Yotastic yogurt cups in the garage for mixing epoxy and doing odd jobs. The cup fits perfectly.

    I agree with your guru. Just weld it up for now. FAIW, I was able to detach the EGR tube from my intake by putting a huge crescent on it, tying a rope through the hole at the end of the wrench's handle, tying the other end around the intake manifold near the throttle body, and pulling up on the rope (which creates enormous mechanical advantage). However, I don't think there's any way of dealing with the other end of the tube. I'd just follow the advice you cite: Cut the tube in situ and weld both ends closed.

    Be warned that if you have annual inspections (not meaning emissions testing, but just a general non-emissions inspection, like here in VA), your EGR might be an inspection item. I think it's illegal to tamper with the emissions equipment. While I don't think you will get fined, I don't think your car will pass inspection. The way around this is to make the EGR tube LOOK like it's intact, perhaps by slipping a tube over both welded ends and wrapping it up with exhaust tape.
    Last edited by FastWoman; 05-09-2011 at 07:05 PM.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

  91. #91
    Registered User grantf's Avatar
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    If it were a "beer can test" people would listen I'll bet. (:

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    I am a little confused on how the repair will be done, will you post pics?

  93. #93
    Registered User Bonzi Lon's Avatar
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    Your
    Oxygen
    Gas
    Union
    Regurgitation
    Test

    Bonzi Lon
    1973 HLS30-168500
    1968 SPL311-18100
    1969 HLS30-000110 SOLD Shipped to Dubai UAE
    CZCC#11300

    Ones and Zeros

    "We drive only blue cars." Dishwalla

  94. #94
    Nova Scotia,Canada,Earth Blue's Avatar
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    lol Bonzi
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
    The person who buys on price alone is this man's lawful prey.


    John Ruskin (1819 - 1900)



    ZCars in Eastern Canada seaport ready for shipment to Europe

    http://ZSportCanada.com


  95. #95
    Z geek at large FastWoman's Avatar
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    YOGURT test. Yeah, I like it, Bonzi!

    But I'm going to check whether a beer can fits the boot.

    Breath
    Exhalation
    Experimental
    Retention
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

  96. #96
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    GREAT NEWS!!!!!!!!!!!!!!!!!!!!!!!!!!!!! All the blood sweat and tears have come to end on this part of the project. I worked with one of the mechanics (at my cousins garage) that has worked on other stuff on my z car. The fix is done, and the car drives night and day different!!!!!!!!!!!!!!!!!!!!!!!!!!!! My wife just drove it for 2 hours and she was really enjoying it. She was patient and knew I would tell her when it was *ready* to actually enjoy. Let me tell you it was fun being over in the passenger side to. I could just listen to the engine purring like I thought it should, and feel the new found power too. It was a complete transformation. We did a lot of little stuff too, that needed to wait for this moment. BUt the main thing is the EGR tube is welded shut. An intake manifold replacement is not expensive, and whenever I feel like it, I will get it, and start tearing into the engine to replace it. It will teach me some more new things. But that aint gonna happen until I get in month and months of driving this year.

    Also I got my kick butt stereo done around the same time. So I popped in one of our old favorite DVD's and she didnt know it, and looked down and was like OMGGGGGGG you werent kidding. It was a kodak moment for sure. It rocks.

    This isnt the end of the story, but it is the end of a book in a series for sure.

    My cousin said engine is sounding sooooooooo much better, and it doesnt stink of course, anything like before. I just need to drive it a lot now and recheck plugs a few times. And tweak the AFM screw, because I think that needs to be done. I feel some heistation or maybe its flooding in the power band between 3000 and 5000. I mean dont get me wrong, but I feel like it has more to give and more smoothly at the higher rpms, but also we can climb up huge hills just fine while acclearting in 2nd gear. But on the interstate it seems doggy in the higher end.

    I am not complaining at all. I just want to make this engine run as exactly to specs are possible. Yes I will do valves pretty soon. But my 3 Z experts are telling me, its OK if I put it off a little longer anyway. I mea my god, there have been so many little problems that have added up to one BIG problem. The car ran like S*i%

    Oh well I could go on and on, as you know. I am going out to check the AFR's with my innovate meter, and see how they are and start the tweaking process.

    He figures the more I drive it, it will clean up those valves that were being assulted by the extreme amount of exhaust GOING RIGHT INTO THE ENGINE!!!!

    I am also going to use a little seafoam at some point, but maybe not for a month.

    WHAT WAS DONE
    ================

    • EGR housing fixed/remedied,
    • Reserve light switch replaced (it was leaking because we found out the gasket on it was in bad shape)
    • Fixed a bolt I broke off holding on the ignition coil
    • oil change
    • spark plugs cleaned
    • New distributor adaptor (because of the other people working on the timing, broke the adjustment bolt off)
    • They checked the distributor while they had it out, and reset timing
    • They put oscilliscope on the car again-->primary and secondary ingition looked good/fine
    • Removed the fuel pressure guage from the car, it doesnt need that anymore
    • I hooked my vaccum lines for HVAC system again (and its still working - unbelievable)
    • tweaked the idle and AFM bypass screw a little (backed it out a lot)
    • Checked engine vacuum was between 16 and 17, and that was before they tweaked AFM, so I think it go even higher once I get AFM dialed in better
    • Installed all new premium connectors on the fuel injector connectors (soldered on), they are bosch styl quick disconnect :-)
    • New plugs, rotor and cap (Yec brand from japan, supposedly very high quality


    No more stinky exhaust either. Now that the engine is running fine. :-)

    Well this is already getting too long. I will post more later in a few weeks, I need time to test and tweak things.

    THANKS AGAIN FOR ALL YOUR ADVICE AND TIPS!!!
    Last edited by argniest; 05-11-2011 at 07:46 PM.

  97. #97
    Z geek at large FastWoman's Avatar
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    Way cool, Argneist!

    Now you're getting a taste of what your Z is like. It's a wonderful car when it's straightened out. You've probably got your engine to 90% of where it should be, judging from your vacuum readings. Try running some Chevron Delo to clean up your engine. And yes, SeaFoam in the intake is probably a very good idea too.
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

  98. #98
    Nova Scotia,Canada,Earth Blue's Avatar
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    These are easy cars to work on.

    Your effort also unearthed a new fault that may become common to these aging cars. It will help others in the future.

    Now enjoy driving

    Philip
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
    The person who buys on price alone is this man's lawful prey.


    John Ruskin (1819 - 1900)



    ZCars in Eastern Canada seaport ready for shipment to Europe

    http://ZSportCanada.com


  99. #99
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    Yes, I believe this problem will happen to others. Poor souls. I hope they find this place! I dont know why this happens. I mean since most people dont have the problem, there had to be some reasoning behind why my Z got infected with this crazy problem. And yup, I am understanding a lot better what the Z should be like. But I believe there is more to go as you mentioned. Cars should keep accelarating when you mash the pedal down, on the interstate or in town. Not be fluttery or wavering.

    So the next thing will be to see how my AFR meter and AFM screw can help me dial it in. I also wonder how bad a z car will run if its (AFR's and the AFM) out of whack. I think after driving again last night I am dumping too much fuel. I couldnt get the Innovate meter to work in the Z, but I stuck it on another car and it worked fine. But then I also found I out I had to really push the sensor plug into the computer black box. So I think that is what the problem was. 2night I should be able to collect the most important data yet, on the AFR's. THen I will come back and look at it on the computer. ANd see what is going on during all the different driving conditions.

    I mean, considering all the things that have changed to be correct now, I am anticipating that the AFR's are going to be a lot better than before. But I believe I am running too rich. And I got too wiped out last night and didnt have time to check my spark plugs. To me, that is the #1 thing to check because I have driven like 100 miles or more on them now, in all conditions. So before I go off on my next test drive I will check them I also believe they will be looking a lot better.

    The engine was kinda too hot, but I pulled #4 FI connector off, and sure enough car engine slowed down, just like I was hoping it would. So I am sure this time, before engine gets too hot, I am going to pull 6 and 5 off, and just be 100% sure its effecting engine when I pull them off. Now that I got the new bosch quick disconnect FI leads on there, they dont just fall off like before :O

    I will leave no stone un-turned in my quest to bring it back as close to specs as possible. I dont care how long it takes.

    HOWEVER, THIS SEASON I CAN DRIVE IT NOW AND ENJOY IT!!!!!!!!!!!!! If I didnt make it any better, that would be OK. However, I know for sure it has more to do. And I got to be sure I am not running around too rich or too lean. THEN I can head off into the sunset.

    PS
    And I think that getting valves back to exact specs will probably bring back a little more normalness too. Its still near the top of my list. First though, they are not that bad, and I can drive without fear.

    Im telling you, I am still in shock. After the kind of excruciating effort I have gone through since last november. Its so cool, now I have a much larger base of knowledge to operate on. And yes, this car IS very easy to work on now that I have had a taste of it. I always thought it should be when just staring at the engine. But from bumper to bumper, I commend the people who designed it!!!!!
    Thanks again for everyones help.
    Last edited by argniest; 05-12-2011 at 02:56 PM.

  100. #100
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    The screw on the side of the AFM only adds air to the idle mixture. It can give a little smoother idle (in my experience) but at the expense of running richer at idle (and failing emissions testing in Oregon). It will have no noticeable effect on any driving conditions, only engine idle.

    The most common cause of running rich on these early EFI systems is extra resistance in the water temperature circuit (or CHTS for later models, but your 78 has a water temp. sensor), usually from dirty connections. You can check the whole circuit at the ECU plug - measure resistance there and compare the reading to the table in the FSM to see if you're getting the proper resistance at the ECU for the temperature. The simplest is to measure at ambient temperature to see if you're in the right range.

    Just trying to save you some time. Don't spend too much effort looking at the screw on the AFM.

    Congrats on getting back on the road...
    Last edited by Zed Head; 05-12-2011 at 04:01 PM.

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