CTS-V Lean to rich at launch

[Sevy]

Hey all,

I'm hoping for some insight because I am a bit green to tuning. I took my car to the drag strip and data logged some passes. I noticed that when I stab the throttle at launch I instantly go to 1.40 and then immediately drop down to .56 until it eventually cleans out to .75-.82. I know that the maf cal needs minor tweaking but what do I need to change to fix that lean-rich issue? I attached a picture of this log and a picture of the PE settings as some other threads talk about PE settings.

Thanks!

[5FDP]

Is desoot mode still enabled?

That can cause a lean spike upon PE.

[Sevy]

Is desoot mode still enabled?

That can cause a lean spike upon PE.

Desoot mode is disabled. Any other thoughts?

[TCSS07]

maybe try lowering the enrichment rate to 1 instead of 2 ... you might be over shooting your target pe ratio and then it has to correct
do you actually have a wideband gauge installed in the vehicle to see if your actually getting that lean spike and its not just a logging anomaly
could you post tune file and actual log so we can see the data

[Sevy]

maybe try lowering the enrichment rate to 1 instead of 2 ... you might be over shooting your target pe ratio and then it has to correct
do you actually have a wideband gauge installed in the vehicle to see if your actually getting that lean spike and its not just a logging anomaly
could you post tune file and actual log so we can see the data

The lean spike comes and goes in about .06 seconds so that to me isn't all that concerning. The going rich for half a second is what I don't like. And is that what is causing the KR? Also you can tell by the narrow band that the car is going rich.

The enrichment number from 2 to 1 might help to slow it down.

[TCSS07]

more than likely, yeah, .56(8.2 afr) could cause some knock for sure because of too much fuel. try the ramp in @ 1 and i dont know when you have pe activated but for boosted applications i set pe to come in around 90kpa to help with fuel enrich while entering boost and if your still shooting way low at first then you need to start adjusting your maf or ve tables - however you have your fueling set up - and lean out the numbers in the cells you hit when you enter pe until they get more in line with commanded afr

[GHuggins]

It's just too much transient - what's manifold volume set to? Have transients been changed?

[TCSS07]

i forgot about trasient fueling being a cause also - sorry i over look that from time to given my car doesnt have that option and i have to engage pe sooner for me