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ECMlink [RESOLVED] 1G Won't Idle when Hot, Choppy Throttle, What do you see in logs?

19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
Honestly curious what everyone sees in these logs. Fairly stock 1990 Eclipse GST: stock replacement fuel pump, 450cc injectors, N/T FPR (supposedly), Evo III 16G at wastegate pressure, hacked air can but otherwise original MAF, FP exhaust manifold, and Link V3.

First, I jumped-started the car while logging and everything is great. Smooth throttle response, smooth idle, etc. Nothing appears too exciting for me. I may have messed with the fuel settings a couple times throughout. But again, everything appears to be working fine.

Second, I was testing to see whether there was a voltage supply issue and if the engine operation would improve while the battery was being jumped. After reaching operating temp and idling for quite a while, idle gets choppy and eventually the car stalls.

As the car started "acting up", it seemed like it would stay in Open Loop. Eventually, it would stall. I actually locked it in open loop once and made the engine stall. The second log is a capture of the idle transitioning from sustaining to failing. What I see is ISC unable to operate properly for some reason (ISC was replaced a couple years ago with working unit, but the old one only kept the car from idling properly, it did not keep the engine from running) and O2 sensor not cycling the way it should, maybe some funny business with the CTS when it starts to stall out.

Third log is, again, trying the car with battery jumped and a different CAS.

Again, kinda just curious if there's anything blatantly standing out to anyone in these logs. These (and many others available) were taken all in the same day in a span of 1 hour and 45 minutes. No DTCs at any point.

Thanks everyone.
 

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  • jump start_good idle_ wBattery.2022.10.01-01.elg
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  • idle_dies_whilejumped.elg
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  • jumped_differentCAS_opclosedloo_idle_dies.2022.10.01-01.elg
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19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
Thanks, Brad. The FPR is a Delphi FP10469 so it should be a N/T, spec'd for a 1990 2.0L N/T when I ordered it. I simply didn't see or feel any difference when I put it on.

I did find a small boost leak at the throttle body that I sealed up and an exposed wire on the harness side for the O2 sensor yesterday. I'll need to sort that out over next weekend.

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Vegas Smith

15+ Year Contributor
5,034
2,904
Dec 2, 2002
Houston, Texas
There's a lot that's messed up here.
1) Your fuel trims are very lean
2) Your airflowperrev is very high; Almost double what it should be
3) Your isc is maxing out trying to keep the idle down
4) Enable airflow smoothing. You're not running speed density.
I would guess you have a big vacuum leak introducing air to the manifold causing the car to run lean, the idle to increase, and the airflowperev to increase. It also might be bad o2 sensor. It's behaving weirdly. You also have an IAT cel.
 

AWD-Tony

Supporting Member
6,796
3,683
Sep 11, 2017
Cincinnati, Ohio
There's a code for IAT circuit malfunction. Global is -11 with 450's and the O2 is always reading lean unless you give it throttle. I'd set the global to zero and make sure O2 swings back and forth.
 

19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
Thanks, everyone - definitely some good things to start looking at. Forgive my noobness on the Link software, trying to make it all make sense.

I was adjusting the global throughout the day. Hence my comment about the supposedly N/T FPR. I realize it is running lean but I couldn't seem to get the right settings for the global to make it happier. Using the little calculator:
  • 450cc injectors with a N/T fuel pressure regulator (47 psi base pressure is what I was using) would calculate out to -11.#% on the global. Even there, appeared lean.
  • I would change the base pressure back down to normal turbo FPR levels (38 psi) to get the global down to -1.#% but overall didn't notice any changes in how things were operating. Still lean, obviously. Looking back at the link to the FPR I bought, it is showing "System Pressure 51". I would assume that's actually where I should be starting at? But wouldn't that make the global more negative? I guess that's not necessarily a bad thing if there's a significant air leak compounding the problem.
  • Oddly, when I started getting into what could be the problem and checked the base pressure, it was calculating based on 43 psi and I'm pretty certain I've never messed with that setting before. More a point of curiosity that 43 psi would be the default for a 1G from ECMTuning.

I'll BLT again and see what I can see. I never noticed the IAT code so I'll have to go back through the log to see what may have happened there. At some point, I did disconnect the MAF connector so that could have been it. Battery is disconnected currently so that should go away next time I get into it.

I appreciate the feedback!
 

19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
BLT again, repaired the O2 wire (really glad that the 2G replacement connector from Sheridan Engineering is sooooo much easier to de-pin than the original connector), set global back to be calculated at 38 psi base fuel pressure (-1.#%), and ensured all DTCs were cleared and, so far, things are looking good. Went back to the "first" CAS so first log is without any adjustments and the first crank after getting things put back together. Second log is resetting base timing and adjusting the BISS. Based on AFRatioEst, it appeared the global was still lean so the third is changing the global by using 43 psi base pressure (-7.4%). This seemed to provide more appropriate values for AFRatioEst.

Any additional feedback is welcome. In any case, I appreciate the sanity checks.
 

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  • globaladjust_43psi.2022.10.09-01.elg
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  • timing_BISS_adjust.2022.10.09-01.elg
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  • fixO2wire_ogCAS.2022.10.09-01.elg
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19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
Yes, that is where it is currently at. I'll revisit this thread next weekend and mark as resolved if it passes all my checks.
 

19Eclipse90

DSM Wiseman
5,276
1,143
Sep 29, 2003
OKC, Oklahoma
I think I'm good with it. Per @AWD-Tony Tony's suggestion (and some of his posts elsewhere in the forum), started logging CombinedFT and adjusted the fuel pressure input for the global fuel caculation where it ought to be for a non-turbo FPR (@ 47psi) so my global fuel is calculating out to -11.7%. I needed to add some 45 microseconds of global deadtime. This put CombinedFT and STFT hovering around 0% and, after a short drive, I saw LTFT learn properly and get there as well.

The test run to the store and back felt good and no issues. So it's going back to daily duties!

Thanks everyone!
 

Attachments

  • plus45us_deadtime.2022.10.17-01.elg
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  • shortdrive_stft and ltft LO good.2022.10.17-01.elg
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  • post drive idle.2022.10.17-01.elg
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