EFI relay unplugged

[rcb280z]

Well I tried adjusting the AFM and I can't find a happy medium. What is so strange is I ran a mileage test today, about a 100 miles, and she's getting 22.5 mpg. That's 90% freeway driving at around 65 mph. I expected a lot more because she really feels like she is lean. Plugs are almost white which would say lean. And seems to have less power. Am I expecting to much out of an engine with 120k miles? My vacuum gauge is showing 18-18 1/2" and sometimes 19. If it were low I would look for a vacuum leak as a culprit. Timing is set at 14% right now. I feel like I'm taking 1 step forward and 2 steps back always with this car. And Fastwomen, I tapped on the ECU a couple of times and didn't notice a difference. If I adjust the AFM right now for a smooth running engine then I will really be rich.

[Captain Obvious]

I'm really sorry, but I'm confused and I hope I'm not asking stupid questions...

as soon as she fired and started her low unstable idle I moved the AFM counter weight forward...stumbled more. Moved the weight back (CW) and she perked right up and idled where she is supposed to on a cold start! So she is running too rich on cold start up due to AFM.

I've not been inside an AFM myself, but I'm looking at pictures and I'm getting a different read on the directions that you are...

Looking at pictures, the counterweight is in the upper left corner, say 11:00, and it appears to me that if you would move the counterweight "forward", in a CCW direction say from 11:00 to 9:00, then you would be opening the AFM flapper and the ECU would add more fuel accordingly.

And if you would move the counterweight in a CW direction, say from 11:00 to 1:00, that would close the AFM flapper, and the ECU would reduce the amount of fuel.

Short story is that it appears to me that CCW is richer and CW is leaner. I know it's just a matter of time until I'm inside my own AFM, but until then... I'm confused!

It was actually a mechanic friend of mine that messed with the clock spring...he adjusted it lean because he thought it would need it to pass CA smog (and it didn't). So after the smog he adjusted it to where he thought I would like it.

When your mechanic was messing with the AFM, was that in an attempt to fix the problems you're having now, or was that a while ago before you started this thread?

[Captain Obvious]

Here's a pic from that great EFI thread on HybridZ: http://forums.hybridz.org/index.php/topic/95316-braaps-l6-efi-induction-advice-and-tips/

This pic makes it look like CCW is richer and CW is leaner:

[rcb280z]

That is all correct Captain Obvious. I'm not sure what you don't understand...you pretty much said exactly what I did. I probably didn't explain clearly. When I started the car (cold) and it had it's typical unstable idle I rotated counter weight CCW and it stumbled more saying to much fuel. Then I rotated it CW (leaner) and it perked right up and idled where it should on a cold start. Hope I was able to clear things up. The mechanic did what he did long before this. About 1 1/2 years ago. I pulled plugs and they look good, I think. I will post pics soon. I also ran a compression test this afternoon. Here are the results: 1-150, 2-170, 3-155, 4-150, 5-175, 6-175. This could be why it doesn't idle that smooth. I did last valve adj. about 4 months ago at the latest. 1,3,&4 are a little low compared to the other three. I will try adding some oil to those cylinders and test them again. Again...grasping at straws I know. Any thoughts? Capt Obvious, let me know that I cleared things up.

[rcb280z]

Here are the pics

[FastWoman]

120k isn't really many miles on an engine. Mine has 170. That said, your compression numbers are a bit uneven -- not enough to indicate a problem, but a bit uneven still.

I'm a bit confused as to where the AFM was adjusted, how it's adjusted now, and how that relates to how it came out of the factory. I think your best bet is to recalibrate the clock spring using Blue's method, and then determine whether the engine is running lean or rich. FAIW, though, a vacuum of 18 - 19 is fairly decent, assuming your vacuum gauge isn't lying to you. Higher is better, obviously. My engine pulls about 18.5. You shouldn't think of vacuum leaks as contributing to low vacuum, per se. Remember that your throttle body is a huge vacuum leak. Vacuum is an indicator of the running efficiency of your engine. Introduce a larger vacuum leak by opening the throttle a bit, and the engine vacuum will immediately drop and then stabilize at roughly the same vacuum as the RPMs pick up. This all assumes that fuel metering is correct and that you're adding fuel too.

If your fuel delivery were too rich, for some reason, and you were to open up a vacuum leak by pulling one of your vacuum hoses, and if the leak were to correct the otherwise rich mixture, your vacuum should stabilize in the neighborhood of 19, even with the leak. See how that works?

Anyway, my advice would be to verify the proper condition of every component of the engine (e.g. no vacuum leaks, properly functioning components, proper adjustment of valves, timing, throttle position sensor, AFM clock spring) and then see what your engine does. If necessary, we can adjust the mixture after that.

[rcb280z]

That is actually the next plan of attack.....AFM clock spring adj. I think I understand what you are saying Fastwomen. Everything is getting a little complicated right now. Thanks for the continued help.

[240260280z]

Your plugs have interesting bands on the ground straps.

It may have to do with timing.

I found this on the net so I am not sure how accurate it is however do some searches on what 280z EFI plugs should look like and also double check your timing.

[Captain Obvious]

That is all correct Captain Obvious. I'm not sure what you don't understand...

Sorry. Got it.

No, you explained it just fine. Haha! I'm pretty sure my post #74 is what a brain fart looks like when you take that time to type it out. :stupid: Well I got that pretty picture posted anyway! That's got to count for something, right?

Back to reality... Seems to contradict the AFM test results, but I agree with you. Those plugs look lean, not rich.

[rcb280z]

Maybe I should put the timing back to factory setting and run it and see if the plugs look different.

Capt Obvious, glad I could clear things up. Back to researching.....

I still need to figure out how to do Blue's AFM calibration.

[rcb280z]

I went to NGK's web page and my plugs look like there is a combination of 2 of the plugs displayed. Mine look normal and at the same time have "dry and wet" fouling look to them. Strange.

ngk.com/tech_support/spark_plugs/faqs/faqread.asp

[rcb280z]

Okay, I'm depressed now.:disappoin Started her up (cold start) and she is back to her unstable idle! I thought I had that fixed at least. There must be something seriously wrong with the AFM. Not sure if it is worth doing the "recalibration" do you? Sorry everyone, thought I was making progress.