M232 about transient fuleing, requested mixture vs. actual AFR

[-ice-]

Hello,

I attached a Screenshot of my first tries to tune

What I see quite often, that the measured AFR sometimes follows the requested AFR very well and somtimes I get something else (more lean not stable). I marked that with the white circles in the screenshot.

I don't know where this is coming from. I thought it might be an ignition timing issue...but even if the knock control comes active and retards the ignition the mixture looks the same.

Does anyone have an explanation for this? What is happening there?


Thanks,

Daniel

[Acki]

Wall wetting effects? Delta load not perfect?

[-ice-]

Do you mean accelleration enrichment by delta load not perfect?

[Error404]

Timing can’t affect AFR since the vales close long before ignition

[-ice-]

Thats a valid point. I suspect a fuel pressure issue here and will measure the fuel pressure next.

[d_anev]

Hi Daniel,
little more info will be useful like RPM curve and what is the hardware and software config i.e. prjmod (MAFless) or stock with MAF.
Why does Dimitri draw more than 30 parameters from the computer, not just a few basic ones? !!! Because most work together and depend on each other and only watched together give a full picture of what's really going on.

Hardware problem is one of the possible reasons, but you have all prjmod extras even on stock software and you can try some tricks.

What ECU doing generally in WOT?! Calculates IPW depending on air mass, corrected by IAT, ECT and etc.
In your case ECU for some reason, calculates less real IPW than necessary. What can be reason for that?!
If soft is stock - MAF "tells" on ECU that the air mass is less than real is for current range of RPM, or in prjmod VE map "tells" on ECU the same wrong info for current range of RPM and MAP pressure. May be your hardware (air paths, catcams, intake, turbo and etc.) produce more air in that range of RPM or MAF measured “what is the weather of the moon” (a quote from Dmitri) or maybe not.

Use Dimitri's prjmod extras, change/play a little with VE map or MAF maps to be able to see is the problem can be solved by software tuning or can't. Then you will have the some directions is there software or hardware problem or both.

Do not exclude all possibilities, but use available tuning extras provided by Dmitri to exclude one by one possible causes. Otherwise, with this approach here, it turns into divination/guessinga by picture. This is not a professional aproach and risk to lead to solution that is faw away from real problem is too big.