noob valve adjusting on 1978 280z

[FastWoman]

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.

[240260280z]

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

[argniest]

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

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.

Edited May 12, 2011 by argniest

[Zed Head]

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...

Edited May 12, 2011 by Zed Head

[argniest]

I measured that (and all the other tests in the EFI bible - and they were all good in spec or very close),

Well after some experimentation last night and some fun driving, I have AFM screw turned counter clock wise 1 full turn, and most of the hestiations etc in the higher rpms are mostly gone. So it sure does seem like it made a difference. I cant get the Innovate to power up in the Z car. Dont know whats up with that yet. I hooked it up to a different car and it worked just fine.

The car is more powerful than ever before, and starting to feel almost like a real sports car. I got several serious adrenaline rushes last night. I wont say why or how....but I did :-) hehehe Talk about bringing a big ole smile to my face, I was actually laughing like....wow!!!! now thats why I love the car. My gosh, the car handles phenomenal powering thru turns the new bigger eagle GT tires help to really dig in too. I upgraded one size with the 15's.

Still though, it feels like the engine accelaration is drifting around at higher rpm's. Like it cant lock in and just go in a smooth line. I dont know the right words to use yet, to explain what I feel. But in other cars, when you romp on it, it just pretty much goes and goes and goes, and there is no hesitation in the higher rpm's.

It seems to me the z car should just, for the most part, accelarate in a constant line from 2000 to 5000 rpms, and not feel like your power is hesitating or dropping out a little, and then kind of coming back, and going out, and coming back. I am not talking about a major event, but I can feel it happening for sure.

I will be glad to get my Innovate working as soon as possible. So I can get some real data. And not just go by feeling and listening. It was good to watch it working on a different car. And I confirmed the numbers with a mechanic friend, and he said those sounded normal for the other vehicle.

Its just like it cant power itself up in the Z car. I am going to basically cut the plug end off, and put clamps and hook it directly to the battery, it has to work then!! THe odd thing is I did get it to work before, two times, in the Z car. but now its being a stuboorn PITA.

Edited May 13, 2011 by argniest

[240260280z]

I used my innovative O2 on a couple of Z's (260z and 280z). I don't remember a problem. Did the ciggy fuse go out? Maybe clean the fuse and ciggy socket contacts as they could have corroded.

For higher rpm performance I would recommend the ZX distributor swap. http://atlanticz.ca/zclub/techtips/distributor/index.html I did it on two '77's and a 240z and the higher rpm's were smoother (All three z owners noticed the improvement).

You may wish to move the AFM's internal tension wheel a few teeth to the rich or lean side and see if that helps higher rpms.

Edited May 13, 2011 by Blue

[Jetaway]

Translumenal Pressurization Procedure

A buddy of mine took his car into the dealer and was charged $450 for the test. Man, am I glad it isn't applicable to carbureted cars.

Chris

[argniest]

I have a lot of good news!!!!!!!!!!!!!!! Basically, my tvs must be bad. I was driving after all the fixes from last week, and changing afm screw, and it was making the afr's a little better, and then i decided it was time to pull of the throttle valve swtich (tvs), it was still on my todo list. Before when i did it, the car ran worse, so i was like ok forget that for now.

As soon as i unplugged tvs, immediately while sitting there idling, the afr's went right to 1 lamba or 14.7!!!!!! And so we took off driving again. The afr's were showing a lot!!!! Better after that.

And my god!!!!!!!!!!!!!!!!!!!! The car was driving amazing, i almost had to clean out the drawers, it was a night and day difference (even from the other day after getting the massive air intake leak fixed) basically, before removing tvs i was showing 9.2 to 10.2 while just driving around!!!!

After removing tvs, everytime i hit a stoplight, it would quickly goto around 14.3 to 14.7, and sometimes when i pulled over and just let it idle for a few minutes, in went into 15's and 16's. I recorded all the data, and have it on my pc. Have reviewed it. I went on another test drive tonight because i just had to. I was more aggresive 2night, because i was alone. Im not saying i was speeding, but i definately took off from every stop light, and was like whoooooooooooooooooa now this is what a z car is supposed to feel like!

Driving without the tvs, showed between 12 and 13 afr in most cases, and then included 30 to 45 and also on the interstate at 65. Sometimes it went to 13.5 afr when just kind of putting along 25 to 30 mph.

This is by far the fastest the car has even been, and this time i could rev it up to 5000 rpms and i could just tell it wanted to do it now. With ease.

I know these are not ideal afr numbers yet, but my god, considering where i have been, and how this car is handling now....its a total dream come true for real. I am extremely happy with how car is driving. I was hauling ##$*$$* sometimes, and felt the g forces this time. Like i used to feel in my 300 zx.

And it really went from 2000 to 5000 rpms in the lower gears, much much more at ease, and more quickly. The engine is purring, and going vrooooooom like its supposed to. A totally different sound, its much quieter at idle, and sound sweet when taking off like a bat out of hell.

Now with all that said, i still believe if the afr data is correct, i am still dumping too much fuel in there, and that could be beacuse i didnt have the tvs on there at all. I dont know enough about that switch yet, but maybe someone can tell me about it, and if it would control the afr's better, if it was working.

Two other pieces of great data as far as i am concerned, i am now getting 20 miles per gallon. By far the best ever, and that was with modest driving, and a few romps only.

And finally when i pulled into garage i let it cool down a little, and pulled all the plugs. Well all 6 of them are the same now. That is a first!!!!!!!!!!!!!!! And i think they look pretty good. Maybe not perfect yet, but so much better, and all exactly consistent.

I am so excited right now i can barely stand it.

I was also told by my relative who fixed it last week, that the more i drive it, the better it should get (like cleaning out the cobwebs from it running on 3 cylinders for god knows how long)

so there you go, i just had to let ya all know! What happened past 6 hours. I would have done this sooner, but it has been raining for days, and i wont get it wet.

Here are two of the current plugs, and the one on the right is what they looked like after the other problems were fixed last week. Keep in mind, after the EGR housing was fixed, the car was of course driving a lot better. But now the two plugs on the left of this picture is how they all look.

Its not any coincidence that the mpg's are much better, the plugs are much better, the power and torque is much better, the overall purring engine, much quieter at idle, no more blub blub blub sound, only VROOOOOOOOOOOM VROMMMMMMMMM sounds. Its amazing this day has finally arrived.

Now I still believe there is 15 to 25% more power to get, if I can get those AFR's into line. Im out of brain power now...will start anew tomorrow! And I know my valves will get done very soon now too. That should help too.

Thanks again for everyones help on this forum. I couldnt have done it without you!!

PS

The reason my innovate meter wasnt working, blush, is because I was getting -12volts on the power adapter I installed....DOIH!!!! Red wire goes in back hehe, black wire on side. I whipped out the multimeter and discovered that, because I tested it on another car and it was working fine. So then I knew I had done something wrong. Um yeah -12volts aint gonna make it work very well.

Plus I also discovered I had to push the sensor plug in a little hard, but then it snapped into place. So it was really those two problems. but now its working like a dream. And I love recording the data and coming back and watching it on the PC.

And I cant believe they charge 450$ for the test. Crap you can buy one for less than half of that. What a frigging ripoff!!!

Edited May 16, 2011 by argniest

[240260280z]

That is great news. Congrats.

You should see the TVS/TPS switch kick in and the AFR change when it does.

It basically adds fuel when idling for smooth idle and when approaching wide open throttle (WOT). You have to rotate the switch properly so that the idle contact breaks @ 1,400rpm. You can't adjust the WOT location without bending switch vanes (not recommended)

Here is how to set it up: http://atlanticz.ca/zclub/techtips/tps/index.html

In the table below you can see the fuel added by the TPS:

- IDLE CONTACTS MAKE (Idle Increment) occurs from "Idle Switch On To Idle Switch Off" [800 rpm to 1400rpm]

- IDLE CONTACT JUST BREAKS (After Idle Increment) occurs when passing 1400rpm

- WOT CONTACT MAKE (Full Increment) Full switch on to Full Switch off [gas pedal ~ 2/3 way to the floor]

The ECU also watches the rpms and goes into a coast mode when the foot is off the gas pedal and rpms are above 2800rpm. The ecu knows the foot is off the gas pedal by reading the tvs switch [idle contacts makes].

A common problem is that the idle contacts short when water gets in... usually after watering the car. This makes the ECU think the car is in coast mode all the time when the rpms rise above 2800. It is effectively a rev limiter.

Another common problem is corroded connector contacts or corroded or fused switch contacts.

Edited May 16, 2011 by Blue
more pictures

[FastWoman]

This is all great news! You might need to lean your mixture out just a bit, so that the TPS can make the appropriate enrichments for idle and WOT without making the mix too rich. I suspect the adjustment would be so minor that you might be able to tighten the AFM's clock spring a bit to do it.

Isn't it great to be pulling strong on all 6?! IMO, there is nothing more delightful than a properly running inline 6 motor. It's the only configuration of motor that has inherently perfect primary and secondary balance -- well, that and a V12, which is essentially two inline-6 motors stuck together.

[argniest]

Yes, it is amazing and wonderful to feel this car the way it is supposed to be. Or at least very close. I figure I am about 80 to 90% back to original feeling of the 1978 280z car experience. Just a guess though. I arrived at this moment in what seems like an eternity, but I also was expecting a lot longer drwan out fight to unlock the mysterious problems with the car! So the fact I am up and running before middle of may was awesome! I also enjoy being a passenger, and feeling the power and accelaration from over there. I still have many little things on my list for the car, but its all very minor in comparison!!!!

I am going to really learn about the AFM, since I have an extra one. And run it through all those tests, and tweaking and see where I can go with that. And I have a new TVS on the way. So that should help keep things more balanced. I just dont feel like messing with the TVS right now. I got a good list of instructions on how to test it (I am too busy to mess with it, a new one sounds a whole lot better, and in the winter I will do these tests):

Here are some instructions from the Z wizard!:

The best thing to do is adjust your TVS first. There are 3 pin connectors on it. The center one is the common link. If you've already installed your quick disconnect on your tvs, hopefully you saved your old connector. Put the old connector on the tvs (without the clip). If you don't have the old plug in then just touch the pin connector in the tvs. You just have to be more careful that you're only on the specific lead. The first test do with the engine NOT running.

Using your ohm meter, touch the center pin connector on the TVS with one probe, and touch the rear pin connector with the other probe. There is no polarity on these tests so color isn't important. You should have zero continuity. Open the throttle linkage and you should get continuity about 2/3 to 3/4 throttle. That is the full throttle circuit. If that circuit is activated under half throttle or sooner, then send me the TVS for calibrating. I can usually fix that problem.

For the next test you'll need to put a tachometer on the engine and then start the engine. The engine should be warm for the next test.

Touch the center pin with one probe and touch the forward pin with the other probe. You should have continuity at idle. That continuity should break approximately 1400 rpm. Loosen the mounting screws just enough so you can lightly tap on the mounting tabs to move the switch one way or the other. Play around with it until you figure out the sweet spot for adjustment. It doesn't have to be a perfect 1400 rpm, 1375 to 1425 rpm for the switch to break connection will work just fine.

The TVS is a very simple switch and it only performs 3 functions. It is an important part of the system, but it's ok to drive with it disconnected for a few weeks. The idle circuit richens the mix a little (approx 5%) and it also engages the fuel shutoff between 2800 and 3200 rpm on deccel. The full throttle circuit gives you 27% enrichment at 2/3 throttle.

Edited May 17, 2011 by argniest