spark knock
joeemy
10-20-2003, 08:02 PM
I have a 1995 gmc 4x4 with 220000km and have spark knock. Any idea how to get rid of it. I retarded the timing a couple of degrees about a year ago but it is starting to come back. Heavier under a load, towing a trailer. Can any one help
GMMerlin
11-15-2003, 07:43 AM
Inspect the EGR for proper operation
You may need to "de-carbonize" your engine.
There is a product from GM called Top Engine Cleaner. It is a pour in product that has been around for years.
With the engine at operating temp.
You slowly pour half a can in while the engine is running then pour the rest in quickly to stall the engine...let the engine sit 12 hours and then start it up and drive it. The exhaust will smoke like hell, but you may soften up and remove engough carbon to reduce or eliminate your spark knock.
You may need to "de-carbonize" your engine.
There is a product from GM called Top Engine Cleaner. It is a pour in product that has been around for years.
With the engine at operating temp.
You slowly pour half a can in while the engine is running then pour the rest in quickly to stall the engine...let the engine sit 12 hours and then start it up and drive it. The exhaust will smoke like hell, but you may soften up and remove engough carbon to reduce or eliminate your spark knock.
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