EFI relay unplugged

[Zed Head]

The AAR just lets air pass by the throttle blade in the throttle body. The only way it can affect the mixture is if it has a leak on the upstream hose. Which is a possibility. I had mine split lengthwise when I tried the FSM test of pinching the hose to check AAR operation.

[Zed Head]

Try running your idle speed screw all the way in while the engine is running. You should be able to kill the engine that way. If not, you have a leak somewhere.

I can't really remember what your current problem is, but that test will tell you something about how well the throttle body is controlling air through the AFM.

[rcb280z]

Zed Head, that's a good test to run. I will try that next. As for the hose's for the AAR, they are new. All emissions and vacuum lines for that matter are new. If you have a moment will you look through this thread. There are actually a couple things going on and they have become a PITA. Thanks for your time.

[rcb280z]

I was able to stall it out running the idle set screw in.

[rcb280z]

Ok here is an update: Started the car this morning and like always she has the unstable idle. So I started turning the bypass screw CCW (leaner) and at 3 full turns she picks right up smooths out and starts idling around 1200-1300 rpm. So like I suspected she is too rich on start up. But after she warms up she runs like crap....too lean. I can't find a happy medium with this car. Oh, and there is 328 ohms at the CTS after warm up. So that is good. ??

[240260280z]

Check you CSV as you suggested.... maybe it is dumping fuel.

Either remove it or simply pull the connector to it.

[rcb280z]

True, I did say that and I should do that. Thanks for reminding me. It is unplugged now. If that doesn't improve things then the next step will be to remove it (CSV) and cap the fuel line. Maybe it's leaking.

[rcb280z]

I started the car this morning with the CSV disconnected and still the same result (unstable idle). It did take just a little longer (couple cranks) to start without the CSV connected. So I know it works. I think my next step will be to remove CSV entirely and plug the supply line, also the mounting hole in intake and start it up tomorrow morning. Maybe it leaks while the car is running.

[rcb280z]

OK, I started this thread with a fuel pump safety cut off issue....fixed that. I've owned this car for years and didn't even realize this issue until another member had posted the problem with his Z! PO had hacked into harness under passenger seat bullet connector and ran a jumper to the fuse panel! I disconnected the jumper and things were fine. The safety cut off in the AFM is working again. Now I am chasing a cold start issue after sitting for many hours. The TTS, CTS, AFM, and TPS are showing correct resistance...verified by other members here. Oh and checked these at the ECU connector as well. Also tested AAR thoroughly! If I lean out the AFM some the AAR works perfect. Cold start, the idle jumps right to around 1300 rpm until it warms up with a lean adjustment. But when warm it runs too lean. Have performed Blue's AFM calibration and I don't notice a change. I say it's lean because it pops a little through the AFM and it sounds like it has an intermittent misfire also out the exhaust. If I richen the AFM a little (while engine is warm) it smooths out and runs good and no misfire. This is what the numbers were as soon as I put it on the dyno, lucked out that day, he was slow. HC-263 (too high), CO-1.8 (max-0.5), CO2-13.0,? NO-335?, O2-1.3, MPH-15.3, LOAD-134.3? This is the 15 mph test. Here is the 25 mph test results. HC-152 (ok), CO-2.5 (max-0.5!), CO2-13.3, NO-130, O2-0.3, MPH-25.3, load-74.6. So as you can see it wouldn't pass smog if I had to smog it right now....in 4 months I will. Other things I have done: new cat. converter, new fuel filter, had injectors cleaned on car, checked for vacuum leaks. Pulling 18.5" of vacuum and if I turn idle screw lowering idle it stalls out so as far as I'm concerned there is no leak. Even when I pull a vacuum line to hook up my vacuum gauge it nearly stalls before I can hook it up. Timing is 10-11 deg BTDC now. Everything is stock except for the air filter and header. Was running Chevron 91 but now run 87. Oh I also replaced the FPR thinking that was the reason the pressure bleeds off over night but was wrong. It still bleeds off but I am ok with that. Fuel pressure is 32 at idle and jumps to, looks like, 40 when I throttle it. Someone here mentioned the possibility of air in the fuel lines. Haven't checked that yet. Oh, all the connectors except the AFM and TPS have been replaced. Everything I have mentioned above that was replaced has happened over the past 1 1/2 years. Last mileage check was 21 on the highway babying the car. If I lean it out to CA smog requirements it runs like crap! I have tapped on the ECU looking for a loose solder joint, no change. I really thought I was going to find it was running too lean but with the numbers above I'm still confused. I also pulled the CSV harness thinking maybe it is injecting too much fuel and that's not the case. Static fuel pressure test was at about 46 psi. I think I have covered everything. Any thoughts? Anyone?

Edited February 23, 2012 by rcb280z

[240260280z]

Another test idea:

Could be weird EFI and voltage sensitivity...just a guess.

- on cold morning run jumpers to your battery from another car

- start the other car so that voltage to the Z is now ~13-14V

- start the Z

[rcb280z]

Blue, in your experience, what should the volts be while the car is running? Shouldn't I get around 14.5 volts at the battery at idle? I remember looking at that some time ago and wondering why I didn't have that. IIRC it was about 13.25. I will look at this as well. I know the Z requires a certain amount of volts for the EFI to function right. For the life of me I don't know why I haven't looked into this more! Probably will get a chance to try your test Saturday morning. Will post results that day.

[240260280z]

Anything over 12.8V will charge the battery. The higher the voltage the more current will flow to charge the battery.

13-14V range is fine.

My "grasp at straw" idea above speculates that maybe the EFI system needs a higher voltage from a warmed up car to work properly, at initial start when the voltage is lower from the alternator , maybe the EFI system does not work correctly (measure air and dispense fuel) until the engine and alternator warm up.