I am seeing a timing reduction at WOT, which (as far as I can tell), is not related to Burst Knock, KR, Torque Management, IAT, ECT or any of the other more common causes. As seen in the attached log file (see start of 1/4 mile run @time 3:23), the timing drops to below 20 degrees when going WOT, even though the Main Spark table calls for 28 degrees.
This is a NA cam/intake LS-1 with CNC 243 heads.
Things i have tried:
- Zero'd out IAT timing retard
- Made High & Low Octane Tables the same
- Disabled spark smoothing
- Zero Over speed idle adaptive spark table
- Doubled Knock Retard ECT Delay; halved Knock Retard ECT Gain
- Verified that ECT retard is not active at starting line coolant temperature
- No measurable KR
The only thing that impacts this retard is setting the Min Spark advance to values just below the Main Spark Tables, but I know that this is not the right thing to do.
Does anyone have other ideas for place that I can look? Any direction would be appreciated.
As an aside, I attempted to log additional retard PIDs, but when I do, my MPVI doesn't record a log file at all; I don't know if there is a limitation on PIDs that the MPVI will log.
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