Is there a "special" value for this somewhere on the PROM, or is it simply taken from the main spark table (the lowest value)? I'm trying to combat a problem with engine knock upon startup.

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'87 IROC 5.7l TPI - original owner!

 

Knock problem on start up? Can you explain this problem? You are aware that the ecm DOES test the knock sensor when it first starts the engine and this is why you ALWAYS will have 1-10 knock counts when you first start your engine.

I have noticed that the knock sensor is more sensitive when I start the engine "stone cold" than when it has been "warmed up" first. Though I have confirmed this on a few motors, I should add that every engine has NEVER had the knock sensor replaced and ALL have 100,000+ miles on them. I am debating about changing my knock sensor JUST to see if this is common with all knock sensors regardless of age, or something that needs to be changed periodically.

 

It's louder than lifters or anything like that. You ever heard an engine that's running on - dieseling? It sounds exactly like that, only very briefly (just a couple of "whacks") - instantly upon startup - just when the engine actually fires up.
This is a very low mileage engine (10K miles). I installed a GM crate engine (and swapped out cam and heads) last summer. Nothing needs to be replaced. I just have some kind of tuning problem.


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'87 IROC 5.7l TPI - original owner!