low fuel trim out of whack

[CP]

So far, so good. No CE light with the new jumper. I got so excited I forgot to take a picture...sorry.

I turned the fuel pressure back down to 37 and reset the idle. My trims are still high, but hopefully they'll go down a bit with time. In the first 15 minutes of my drive, I saw for the first time the high trim dip below 100%. It's up around 115% now, but we'll see how it goes for the next few days.

I couldn't have done this without Jeff's invaluable help! THANK YOU JEFF /ubbthreads/images/graemlins/grin.gif

I'll keep updating my progress, so stay tuned. SAFC will be here next week...

 

[CP]

What injector would this correspond with, and is there anything in the logger that I can look at to see the effects on that particular cylinder/injector?

 

[CP]

I've got more fuel trim strangeness going on with my car.

Jeff has been playing with the timing maps for me. The first chip I've been using for about a year had worked pretty good with my setup. I had all the trims right around 100%, but I was getting up to 16 counts of knock sometimes no matter how much I messed with the SAFC. A/f's were between 11.8 and 10.5. The knock was the issue with that chip.

I was told to set the base timing back to 3*, which cut those knock numbers in half, and made the car much more lively.

Recently Jeff burned another chip for me. The idea was to mess with the timing maps to get rid of the knock, and get the base timing back to 5* where it belongs. The only changes I can gather he made to the chip from looking at the chip description printout compared to the last one:

"30% expanded maps"
"15* timing on top map"

I've actually had two chips with these settings. With the first new chip, the car drove alright for a few days but then all the trims pegged at 81%, the idle started creeping up, and it was blowing a bit of smoke out the tailpipe. I didn't touch the SAFC settings, which were all right around 100% with the previous chip.

The second new chip had the same settings. He guessed that I'd killed the first chip when installing it. This time I grounded myself, wore latex gloves, and made sure not to touch any of the chip legs upon installation.

After a few days the trims were all heading downhill again. So the car was running mega-rich. Since then, I've more than doubled my low settings on the SAFC to try to get the trims to come up:

Old chip low New chip low

1K: -7 -17
2K: -6 -10
3K: +1 -5
4K: +1 -5....

This has helped for the most part. My mid and high trims are in the mid-90s now. But my low trim is all over the place. When I got to my driveway this afternoon and stopped, I watched the low trim go from 108% to 81% in about 25 seconds and remain there, and I didn't touch the SAFC.

Anyone have any ideas as to what may be going on to:

1) cause the car to run SO rich with the new chip, given that the only changes were to the timing maps?

2) cause the low trim to move around so quickly and tend to stay in the low 80s?

 

[s_firestone]

CTPS? TB Butterfly gap? Bad condenser(by the coil)? You could have some RF noise infiltrating a connection somewhere. Leaking injector? Fuel pressure fluctuating at idle(unstable pump voltage) or pulsation? Could the AFC itself be contributing to the problem? Coolant temp sensor or connection?

Does it happen when slow rolling? or only after you stop?

I would pull the plugs and see if its just in one cylinder or if all of them are the same then its something fooling the ECU.

 

[CP]

All trims returned to normal operation (100% +/- 4%) when I re-installed my old chip last week while Jeff burned another one for me (cuz he thought the first one was bad).

 

Cy,
Are you still using a Cyclone on the Purge Solenoid?

 

[CP]

No, I sold that to someone, and never installed it. I can't remember if you deleted it from this new chip or not, but the parts are long gone.

I've gotten my trims looking pretty good today. Low to mid 90s for the mid and high trims. The low actually hit 100 for a few minutes today before taking a dive back to 81%, and then began coming up again. That's with my SAFC low 1K setting at -19. I'm going to play with it a bit more, but I don't understand why the low trim moves around so much...and so damn fast. It just plummets down to 81% at times. I can either be creeping along in traffic, or idling at a stop when this happens. I've never seen it do this since I've owned the car/logger.

 

[CP]

I'm all set now, with the trims all within 5% of 100. The 9 hours of driving this weekend helped.

1K: -19
2K: -15
3K and up: -8

My EGT at a steady 85mph cruise is a shade under 1550* in the #1 runner. Now it's time to get the WOT settings figured out.