Could the timing be the cause of the rich readings? You would think that late timing would have the mixture still burning in the header, such that more oxygen was present, but it's also a kind-of-known thing that advancing the timing makes the same AFR read leaner. It makes sense from the standpoint that retarding makes less power and therefore needs less fuel. The question is how profound is this effect? 25%? Every time the timing drops the O2 signals go high. Unfortunately, we can't see what the pulsewidth is doing.
I think the timing is causing the rich readings simply because the short fuel trims are following the timing drop. Right at 1850 rpms the timing drops 20 degrees and the short fuel trim drop to negative 17.
Does the timing dump just based on TPS, or is it kicking in at 1600RPM? I think there are a couple of thresholds there, like abuse mode.
If I keep the rpms low it won't drop off, it just lugs away at low rpm. More throttle, the harder and faster it falls on it's face. Keep in mind I wheeled this way for several days and ran 50+ gallons of gas through it.
Is it possible this is a transmission error? Like it wasn't properly set up for no VSS and no auto transmission control? It wants to shift or is waiting for the shift to finish, but it never does and it's stuck in torque management.
@Bent77 brought that up as well. As far as I can tell and understand, all that shit has been disabled. It was also discussed on the phone with Howell today however I really don't know for sure what tune I have, only what they think I have based on their records.
I just received a shipping confirmation from Howell, the PCM will be delivered tomorrow AM.
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