Quote:
Originally Posted by brn12345
Did a log of my cold start this morning to get a better idea of the resonance. Noticed that the ignition timing during that time is -8 and then moves to +20 when the resonance goes away. I am now more than sure that this is related to heating the cat on cold start. Looking into the tables, I found a table that apparently is for Timing after start. The values in that table are negative and I assume they would modify global timing to be significantly retarded. You might want to reduce the negative number in those tables say from -15 to -5. I think that would solve the resonance, but would it negatively impact something else I don't know.
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Yes, this is the cat light off strategy, retarded timing (and probably late injection) heats the cat more quickly. Messing with the target idle in this area or the after start ignition timing is likely to cause a CEL.
In the past i tried setting the after start timing to 0 rather than -10, but that resulted in large cold start idle speed target errors, a higher cold start idle speed, and a longer wait time before it exits the cold start loop. It did reduce the volume level a little bit though.
Either not all the cold start logic tables are defined yet, or the cold start logic is not exposed to table inputs.