argniest

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?

Yeah, I triple and quadruple checked my compression and leak down test numbers...once I learned how to do them. So I think they are good numbers to go by, and I am not leading on a wild goose chase based on bum data Of course I know they would have been better hot (and with the throttle plate/flap open). I realized that now in retrospect. So I am just assuming my psi readings would be even higher if I did those things.. Well OK, its sounding like I could put my rocker cover back on, and then do some of these other tests. And hold off on the valve adjustments until later. Everyone is being so helpful with so much information!!!!!!! I think I should start it up and try some of these tests. What are chances a brand new injector isnt working? I got them from my Z guy who has been working on these for 30+ years and only sells good quality stuff. And you know what, I think the car IS making a chugging sound. I mean its so hard to explain coming from an apprentice like me, but yes, I would say it chug chug chugh chughs down the road. It seemed worse before those local mechanics changed the timing last week. now it seems less noticable. but still there somewhat. I dont know if changing the timing changed the chugging of if its just *ME*. And also, after they changed timing, I took off from their shop and the car had more power than ever before. But I know the engine is still all messed up. Im just saying...it had more power when taking off, it was smoother accelarating, more power up hill, definately more power available between 3000 and 4500 rpm's. In fact I never even heard the car sound that way before in the power band. But then, we have the bad looking plugs and bad gas mileage. It seems I need to start up engine, pull #6 spark plug wire (NGK) and hopefully not get electrocuted when I do it. I have never touched them when it was running before. SCARED! But you know I think I saw those other guys pull them off when they were playing with the timing, etc. I would like to one by one, pull each spark plug wire, and listen to engine, and take note of if it changes engine sound. Also, shouldnt I do the same thing with the fuel injector connectors? I mean if I pull the electrical connection to each injector, shouldnt it make a very noticable change in the sound of the engine???

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!

:stupid: 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.

I took compression test and leak down tests when cold, well, because I had the car jacked up and in pieces...so I had to. The leak down tests showed like (from cyl 6 to cyl 1) 15, 18,19,19, 18, 22 and compression was like 150 150 155 145 150 140. But engine was cold and also I didnt know to open up the throttle body/flap. I had slightly pushed off the rubber boot from the back of the AFM, but that was it. I didnt take it off, just disconnected clamp and pushed it off a little bit. So I have been told that could have effected my compression and made the numbers lower than they could have been. Possibly even 5 to 20 psi lower, because of the way I did the tests. But its the best I could do at the time. If i could borrow my neighbors large compressor, i could do them again with engine warm...and figure out exactly what to do about throttle this time. If it would be helpful, I could do that again. I listened to all the injectors with a stethescope and I could hear them all clicking away making the same kind of a noise...at least as far as I can tell. It seems they are all working. So that was another reason, it got bumped down the priority list. And all my injectors are brand new too. Im not saying they couldnt be bad, or that I didnt foobar installing them... One my local mechanic friends also did that too (but he used a screwdriver), and said yeah they sound like they are working. We sprayed carb cleaner all over the place by the injectors and intake manifold, didnt make one ioata of a difference in sound of the running engine. FUEL INJECTOR CONNECTORS....I have brand new ones sitting on my parts bench. They are the quick disconnect type. I havent got around to putting them on yet. I have been a little worried as usual about doing that job, so its on hold for right now anyway. But I mean if I can hear the injectors clicking (I have checked several times now), then that tells me the existing connectors much be working. However, with that said, the connectors themselves do not stay on the injectors very easily. I mean they are pretty easy to pull right off, I have never liked that. It seems my engine is going insane and me along with it. One plug clean, two plugs rich?, three plugs maybe lean. But from what I read grey or tan coloring is OK. And its really hard to tell from the pcitures of the plugs, but they seem to be somewhere between gray or tan. So I was thinking 3,2,1 were all looking sort of OK. BUt hey, what do I really know anyway

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/showthread.php?41965-A-few-Questions-about-AFM&p=361195&viewfull=1#post361195

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.

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

Well I figured I better post the picture, because I was somewhat baffled how 3,2,1 all seemed to be very similar, and I think are looking OK. But 5,4 are not good, and #6? its like not even burning in my eyes. The thing is, the local mechanics hooked up a oscilloscope with a two tablet computer screens (one big one and a smaller one) and said nothing was missing. I watched them run the test and looked at their computer screens. Of course I have never seen that procedure done before....so the be honest I didnt really know what I was looking at. But they claimed burn time was good, firing pattern looked OK, and other parameters were OK too with the secondary ignition. I didnt really understand all that stuff yet. If the timing was off, would that cause #6 to be like that? Those guys did play with the timing, but they thought the valves needed to be adjusted, which was the main cause of the lower vacuum of the engine. And then they said they could set the timing, or dial it in better. And yup, I am working on removing rocker cover today, and checking valves. I got another thread going about that :-)

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.

Also, I thought it might be good to show a recent pictures of my plugs based on how the engine is currently running. The plug on the left side is #6, and going to the right side of picture is #1. I have driven it a little more 100 miles? since these pictures. Plugs 3,2,1 seem a little more like tan than gray. Plugs 5 and 4 are always kinds of black. But since this picture, they are starting to look like they have a little brown patch on the tip and not quite as black. Remember my timing was recently changed. And most interesting to me is how #6 barely looks like its being used. I mean shouldnt it have something on it?

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....

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 !!!!!!!!!

In the little bit of moving the air flow meter bypass screw (the one on the firewall side only) another mechanic did while the car was running last week while at his shop, it made a noticable difference in the engine sound. He 'said' it richened it up. Ill bet it did, I am getting 7 to 8 mpg....but that is a whole other story over here.....http://www.classiczcars.com/forums/showthread.php?41966-noob-valve-adjusting-on-1978-280z Im seriously looking at getting that CO meter. I have saved up some $ and its more affordable then I ever thought a CO meter could be.

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.

So, when you are using this meter, how (or what) are you adjusting on the car, to adjust your CO readings? I am reading over what someone just wrote back to me above, and it seems like there are not many things to actually adjust in this old EFI system in the Z car. Basically you have to get rid of any/all vacuum problems, and make sure your valves are proper, timing proper, and good fuel delivery system/EFI system from gas tank to injector. I mean, those are things you cannot tweak. They are just there, and neeed to be working properly.

BTW conedodger, I did replace fuel injectors :-) just a few weeks ago with brand new ones (that was NOT an easy process for me, but I was very thoughtful and careful and the local mechanics who did the smoke tests, ingition testing with oscilliscope computer, and timing changes, (as described in my other post) thought the FI's were fine. Also, you can hear them all clicking the same degree of loudness when you listen to with a stethescope). Also, yes, I replaced every single fuel related hose from the tank to the injectors, with EFI rated hoses where needed, and I cleaned metal fuel rail while it was off the car, shot carb cleaner thru the metal fuel lines under the car a bunch of time, which did remove a little debris. Did it until they were clean looking from bucket contents that it was emptying into. And I installed that G3 fuel filter back by gas tank, so I can see into it, and tell if anything is getting into fuel system. but with the gas tank being cleaned and sealed, I should hardly ever see anything in there, unless the gas station has bad gas storage tanks. And there are no fuel leaks anywhere. I have checked many times now. Those hoses/clamps are good. I also had the local mechanics dbl-checking my clamping, and they said I did a good job on all of them. And they did the smoke test for 5 minutes and we didnt see anything anywhere. No smoke coming out. It made me feel somewhat better that I dont have any vacuum leaks. Their opinion was I DONT HAVE ANY INTAKE VACUUM LEAKS I want to agree with them, but am not 100% sure of course. I have found and fixed some cracked/split hoses this winter. And I thought I have clamped down any loose hoses like on Aux Air Reg for instance. Does that help with what you said above...? HEHE :-) ADJUST VALVES. I am hoping with help from a friend and your guys advice to be doing a valve inspection starting 2night. And adjustment if needed. Ive got to get get a good quality ft-lb wrench tonight first of all, but I have the feeler guage set and wrenchs I need otherwise. I am very hopeful that valves will need some adjustment and after doing it, she will come back to life much more than now. I mean as its driving now, I could live with it. Because it is running better than ever before. However I am getting really bad gas milage, so I know I cant stop yet. Valve adjustment could be THE TICKET!!!! It may not solve all remaining problems, but I feel like it could give me the most bang for my dollar and a half. I will also be checking the TVS as soon as I can. I know that can cause problems. There are soooooooooooooooooooooo many pages and pages and pages and pages of troubleshooting procedures between FSM, EFI bible etc. Its very daunting. I mean I have done some of the recommended things, and repalced many old parts with good quality name brand OEM where possible, parts. And I will keep at it, but I just hope I can get the valves adjusted and see a good performance gain out of it. I will be relentless to go through every diagnostic procedure that seems to apply to my sitation. But it will take me a long time to figure them all out. I have learned a lot about the car since getting hands dirty for past 6 months, slowly but surely, but have a much longer way to go!!!!!!!!!!!!!!!!!!!

Its kinda of funny and interesting to me, why we need two screws on the AFM that apparently do the same thing. Is it just so that they can let air bypass equally on both sides of AFM body? Does adjusting them serve the purpose of adjusting the CO of the engine? I still have a lot to learn about my engine and how it relates to CO settings. How is the CO adjusted when car is running down the road? I suppose the answer to that, is to have your engine is good working order and then it *should be* OK. It sounds like these two AFM screws are only when car is sitting an idling. Is this the device you have: http://www.amazon.com/Gastester-portable-powered-exhaust-analyzer/dp/B000RT8ER0 I also found this one: http://www.etoolcart.com/gunson-gastester-portable-exhaust-gas-analyzer.aspx for less than 300$ hmmmmm I also thought someone was telling me that measuring CO without being able to also measure HC's at the same time is kind of pointless. But I dont remember anywhere in our manuals that says anything about measuring HC. They just have the specs on measuring CO from what I remember anyway.

Well yes, I have the innovate LM-1 meter hooked up now with the exhaust clamp. And have run two tests so far. I had a local mechanic doing some other testing if you read this thread...you can find out more about what I have been doing lately. http://www.classiczcars.com/forums/showthread.php?41966-noob-valve-adjusting-on-1978-280z As far as AFR numbers, well that are not looking good at all. WOT is like 10.1 or 10.2, crusing is averaging maybe 12.5. Idling seems to be very lean now at least around 18.x, but I am pretty sure I saw the AFR LED screen showing 25 to 29 AFR when sitting at stop signs. This gets back to my low vacuum condition I am getting close to adjusting valves. That other thread above is where I am asking for help on that issue. I made a video of the innovate tests results during the two test drives. So some friends of mine who dont have the software could at least see the AFR data as I went on 44 minute long test drives because I ran the LogWorks software, and captured screen videos and added great color commentary and saved the screen videos as wmv files. It seems from what I remember reading, that the AFR bypass screws are used to make CO adjustments. But one thing I was wondering, do both the screws only effect at Idling? Or is one of them made to adjust for when car is running down the road and NOT idling? And why are there even two of them in the first place? I would kind of like to understand that a little better. Thanks PS Is there a CO meter that is affordable? It seems when I was looking a while back, they were all pretty expensive for my tastes.

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.

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.

This is going to be long, but I know you guys/gals like data, so I am trying to preempt most questions. :cool: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!

I have a 1978 280z 5 speed. It has the AFM on it, that has an air bypass screw on both sides of the AFM. Can someone tell me more about them, when to adjust them, when to leave them alone etc? I searched the forums and didnt really find what I was looking for. For one thing....turn CW will richen the mixture and turning CCW lean it out, is that right? What is the way to adjust the CO readings on the car (assume a normal running engine)? Do you just need to adjust the AFM screw(s), or do you also have to adjust the air bypass screw(s) too? Lastly, does the idle adjustment spring and the AFM air bypass screws work in conjunction with each other? I dont understand yet how adjusting one, will effect the other, and vice-versa. It seems if I would turn the AFM bypass screws to richen or lean out the engine, that its going to effect the idling speed of the engine because more or less air will be going into the running engine. So it seems like if youre idle is set OK to say 800 or 900, but then you need to adjust the AFM screw in order to change the CO readings, in the process of doing that, the idle is going to change. SO it seems like a cat and mouse game. I do have an innovate AFR meter at least, so I can get some readings. But I dont have a CO meter to monitor that.

I cant seem to find such a video on that site. Anyone know where its at :-) I would like to actually see it being done. Thanks

Does anyone still have these videos? I would purchase them from you for a good price. It would be very helpful to me. I am sure they are not available anymore.... I want to learn how to read my valves and adjust them as needed on my 1978 Z car with the stock 5 speed manual transmission. I have replaced/renewed everything from the inside/outside of gas tank, all the way to the fuel injectors. I replaced fuel pump, damper, elec connections, all fuel hoses, cleaned fuel lines, removed fuel rail, replaced fuel pressure regulator, PCV valve, and all injectors orings and FI hoses, fuel filter...etc And now I want to learn to do the valve adjustments. Have never opened a valve cover before.