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ECMlink Weird Idle and Cruise AFR

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odion1776

Probationary Member
5
2
Dec 3, 2020
Seattle, Washington
My car has been having some weird idle/cruise afr. Somedays, the afr is perfect (around 14.7) at idle/cruise but other days it runs super rich. I've attatched 2 logs that were taken on the same day less than 2 hours apart, one log the afr is good but the other one it idles/cruises pretty rich. I just got the car and I've been learning about tuning it but this issue has confused me because of how sporadic it is. Also the car is running Ecmlink v3 with speed density. Any help would be greatly appreciated.

-Aidan
 

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  • loggoodafrsameday.2021.01.24.Sun-02.elg
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  • logrichcruiseidle.2021.01.24.Sun-03.elg
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I can't read your logs personally but the ecu will always try to trim the afr to 14.7 during cruise/idle/light throttle

If it's not adjusting the short term ft during the rich situations it's probably not going into closed loop operation

If I remember correctly coolant temp generally needs to be 180+ to enter full closed loop operation where the long term trims update
 
Are the uploaded logs unreadable? or do you not have the software? I'm pretty sure it's in closed loop unless ecmlink is logging the closedloop data incorrectly. There is a 1 next to closeloop on the log file. Coolant temps were above 180 for the entire log except one point where it dipped to 176. STFT was at -10% most of the log.... I also just noticed while looking over the log that I'm only pulling around -8psi vacuum, I will go check for boost leaks.
 
I noticed that when the car does run richer the MAP sensor is reading a lot less vacuum. Your airflowperrev doubles in this instance so I suspect it's developing some kind of vacuum leak. Perhaps the FIAV is leaking? You need to do a solid boost leak test and check out the status of the FIAV. Or maybe the POS omni MAP sensor is messing up? Not sure.
 
I did a boost leak test this morning and there wasn’t a single leak....could the wideband sensor be going bad? (It’s running an aem wideband) The issue is really weird though because I drove the car today for about 2 hours after the boost leak test and I didn’t have a single issue
 
I've had two AEM UEGOs go bad. Both of them would run just fine for maybe 15 minutes, then over about 2 seconds go full rich and the car would sputter. Then it would over another 2 seconds return back to 14.7:1 and repeat. This constant oscillation that AEM support diagnosed as a failed controller yet refused to warranty. The boost gauge also failed (over the course of a drive it would develop an offset, claiming that atmospheric was actually 14 psi of boost for example) and I have been happy not owning another AEM product ever again.

I haven't viewed your log (too lazy to boot the laptop) but I'll see if I can find the video of my old wideband.

That was easy:
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Idk if this is similar to your problem or not but it seems to be a common failure mode for AEM widebands since both of mine failed in the same way.

EDIT: I just realized that's a GlowShift gauge. So I guess completely ignore everything I just said. Except the AEM boost gauge failure, since I still have the AEM support emails for that one.
 
Last edited:
It doesn’t oscillate it usually just stays rich (~10-12) at idle/cruise. The issue hasn’t happened though and I’ve driven the car all day today. I will monitor the issue and post if anything else goes wrong. Thanks for the help everyone.
 
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