Hey guys, I'm tuning my '08 Z with GM stage 3 came and have the Maf calibration pretty spot on. I'm running into an issue with the STFT adding as much as +10 during idle, bumping the AFR to around mid 15's and low 16AFR at times. When turning off closed loop in the scanner the AFR immediately goes to 14.7.
Why is the addition of fuel in the STFT make it leaner?
Thanks in advance
Oh I forgot to mention I have the LTFT disabled
Increase your MAF values for the idle cells by 2-3% and watch your STFT's, your WB is off, the STFT's are telling you she's running lean at idle. now, this could be caused by exhaust reversion depending on how big is the cam, the 02's are more accurate in CL than your WB anyways. once you've increased the MAF cells for idle, use the compare function against a stock cal, and make sure to smooth out the MAF curve using the stock one as a reference for the cells you just modified.
Last edited by bluegoat06; 11-22-2010 at 12:36 PM.
I believe it's a +40 deg overlap cam.
You might be better off running SD tune.
actually just do some narrowband low-hz maf tuning and see if it clears out.
MAF tuning should be fine since you aren't going whacko with boost or anything. Add the corresponding percentages to fix the error. Why it's not reading correctly though, I don't know. Can I haz a Stage 3 Came too?
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Your wideband might be wrong. Even on cams with excessive overlap, my wideband reads roughly stoich at idle in closed loop.
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