Hello all,
I've got a 416 CI LS3 swapped into my C5Z. I street tuned it and have it pretty well dialed in when ECT is at operating temperature. The issue I'm having is that if I disable the MAF and run speed density, cold start AFR is INSANELY lean compared to commanded AFR (wideband maxes out at 20:1 and it sits there), but it's a bit rich once completely warmed up. If I enable the MAF, my AFR is pretty close to commanded. So this is only a problem when I run speed density vs MAF/blend.
Whats interesting is when cold starting, the MAF value reports ~16 g/s of airflow, but dynamic airflow is only ~12 g/s. However, when warmed up, the 2 agree. Where the fk is this discrepancy coming from and how do I fix it? My band aid has been just to run blend tune and it mostly uses MAF airflow, so it mostly works.
Everyone suggests adjusting the OFLA table or the after start enrichment parameters, but that would just command a richer AFR (applies to MAF and VE), rather than fixing the root problem of the VE model at cold ECT is junk
Uploading a tune of me driving home. I tried messing with the VE correction factor vs ECT table, but some more reading seems to suggest that it's a table for transient filtering for when operating in blend/MAF mode, rather than correcting the VE table across ECT.
That's the wideband start up sequence. It warms up for 20 seconds and has a fixed output for specific times so you can calibrate easily. Then it shows measured output. You'll see the narrow bands also agree with the wideband.
I believe the wideband and narrowbans. When I run MAF, the car is noticably smoother with a richer idle since the airflow estimate is correct.
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