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Potential Tuner
L29 0411 swapped, way leaner than commanded on cold starts
I've got a mostly stock L29, rebuilt by me a couple years ago. Shorty headers, no EGR, no Cats, 0280155884 22.2lb@4bar injectors from 5-0 motorsports. I'm tuning using an AEM UEGO 30-0300 wired into the EGR connector, using their supplied formula for AFR conversion (voltage*2.375)+7.3125. Running E10 fuel and a programmed Stoich of 14.17. On cold starts, it runs at 20-30% leaner than commanded AFR, as it warms up it gradually comes back down to +/- 2% over the warm up period. Its currently using MAF only, dynamic and LTFT/STFT disabled, as that's what I'm trying to get dialed in right now. I notice that if i use the command AFR function in the scanner, and try to command it richer, the actual AFR reading doesn't budge. I'm attaching two log files. One is of a complete cold start. The other is after 15min of rest, and an ECT of about 170f, where it does the same thing, just to a lesser extent.cold start lean, maf step 10.hplwarm start lean, 15min rest, maf step 10.hplsquare 1 MAF 10.hpt
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Senior Tuner

Originally Posted by
TheSASquatch
I've got a mostly stock
are you going to be running it for the next 20k miles with a wideband or are you going to put stock O2s back in?
Meaning, use the wideband to tune above 4krpms/WOT and use the lt/stfts to tune everything else under 4k like millions of cars on the road.
makes it so much easier
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Does it run bad when it does that or is it just a number you don't like seeing?
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Potential Tuner
It does run ok, a bit rougher than when its at 14.17 though. Ill finish getting MAF and VE dialed in and then revert to stock o2's and see if it figures itself out. My worry was that 1. Its doing something i cant explain or seem to control (very new at this though). 2. I'm worried it'll just set the stft to 20-30% to compensate while it warms up since I will have stft OL enabled by then. BUT, ill finish what I'm doing and put it back to stock and see if I'm just over thinking it.