FeetDry
January 28th, 2009, 07:15 AM
When doing a WOT run, the engine will burp through the intake at the shift points. It does this with a stock tune. I'd like to get rid of this behavior.
I suspect it is the torque managment that is doing it. The shifts are fine. It is only a problem when shifting @ 5000RPM. I'm thinking it is pulling so much timing to reduce the TQ output, that the charge is still burning during the intake cycle.
I'm not sure where to fix this. I don't see anything in the trans table area. I'm looking at the spark tables: B1027(min spark timing), B7970(retard vs %TqReduction), and maybe B1040(optimal timing).
Min spark timing is set to 7 at the shift RPM's. I'm not sure how to read this chart, but I'm thinking this means the latest spark will happen no later than 7' ATDC. If this is working correctly, 7'ATDC doesn't seem to be enough to cause an intake backfire.
The optimal timing table say's -46' @ 5000RPM. The TqReduction table say's to pull 45' @ 100% Tq reduction. The math say's fire @ ~TDC. I'm sure that won't cause a BFire.
Have you seen this before? How did you fix it?
I suspect it is the torque managment that is doing it. The shifts are fine. It is only a problem when shifting @ 5000RPM. I'm thinking it is pulling so much timing to reduce the TQ output, that the charge is still burning during the intake cycle.
I'm not sure where to fix this. I don't see anything in the trans table area. I'm looking at the spark tables: B1027(min spark timing), B7970(retard vs %TqReduction), and maybe B1040(optimal timing).
Min spark timing is set to 7 at the shift RPM's. I'm not sure how to read this chart, but I'm thinking this means the latest spark will happen no later than 7' ATDC. If this is working correctly, 7'ATDC doesn't seem to be enough to cause an intake backfire.
The optimal timing table say's -46' @ 5000RPM. The TqReduction table say's to pull 45' @ 100% Tq reduction. The math say's fire @ ~TDC. I'm sure that won't cause a BFire.
Have you seen this before? How did you fix it?