How do the various tables and constants that affect spark advance interact? The main tables/constants I am aware of are: initial spark advance, warm and cold spark bias, main spark table, and coolant compensation spark. From what I read, the formula for the advance as seen by the engine should be initial advance - bias + main + coolant comp. I don't think that can be right because it gives way too much advance based on the .bin file that I have developed vs factory recommended spark advance. Could the coolant compensation be some kind of multiplier rather than an adder?

Along the same lines, is there a constant someplace that defines where you switch from cold spark bias to warm spark bias?

I'm pretty new at this. Hope these questions aren't too stupid.

Thanks,
Druber

 

http://www.diy-efi.org/gmecm/papers/747spark.txt

RBob.

 

Perfect!! That clears up some other questions too.
Druber