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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My first experiment was raising the idle in all of those tables to 2000 for everything below 50°F. That did work, however I think your right. There is more at play in the early morning resonance. Retarded timing and possibly early exhaust valve opening would make a lot of this noise trying to warm our non-existent catalysts.
Do we need a new thread to share research on this?