Miss or lean hiccup when accelerating from low rpm at WOT

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04-28-2019
4wheelinls1

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Miss or lean hiccup when accelerating from low rpm at WOT

Attachment 89231 Attachment 89232 Attachment 89233

I have an issue with a PD supercharged LS3 and a persistent lean that occurs at high load from low rpm, typically 1500 rpm or lower, I can replicate it on the dyno or on road, the rate of acceleration needs to be slow or even at a static speed. if you go WOT the mixture is good as the 02 sensors shown, after a second or so the car hesitates and the mixture goes lean, if not accelerating it stays lean, if accelerating it does return to rich.
The commanded fuel, airflow, volumetric efficiency even injector pulse do not alter. I have seen this on a number of occasions with different cars, autos will kick down and its not noticed but this is a manual and he drives around in 6th so its an issue.
I have tried tuning in an SD updated OS also in VVE and then also with a MAF/VVE like stock. I haven't attached a tune as I have 3 different versions. It occurs after the transients would stop, a good second after the pedal has stopped, I think it could be related to the predicted coefficients which I zero in modified cars.

Any ideas welcome.
04-28-2019
MakesBadDecisions

Injector Desoot - possibly under fuel - general - injector control all the way at bottom if enabled you should disable and re-test. That may be your issue.
04-30-2019
4wheelinls1

Quote:

Originally Posted by MakesBadDecisions

Injector Desoot - possibly under fuel - general - injector control all the way at bottom if enabled you should disable and re-test. That may be your issue.

Thanks, this resolved it.
04-30-2019
MakesBadDecisions

Glad it was something simple
05-01-2019
anniversaryss

What is injector desoot?
05-01-2019
TCSS07

anniversaryss - i pulled this from another thread ... Not really a lean tip in. It will enter PE as commanded, then it will drop injector pulse width during desoot at a pre-determined time interval.. It will still stay commanded at PE level during this condition.
05-01-2019
MakesBadDecisions

Quote:

Originally Posted by anniversaryss

What is injector desoot?

Not 100% what and why. After the Desoot was found it "fixed" the momentary lean tip in stuff. Just something I automatically turn off. I would speculate it is part of some emissions shenanigans.
05-07-2019
4wheelinls1

It can happen outside PE, that was one of my issues. My thought on use is that at low rpm where reversion is high and load/throttle opening is high it uses high temp reversion gases to flash the injector tip to clean it.