1997 Chevy Silverado spark knock

JSMID

MEMBER
1997 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
15,500 MILES

I have a terrible spark knock. My repair guy has replaced plugs, wires, cap and rotor, fuel pump and filter. Also several sensors were checked with new ones. There are no codes. The timing showed to be fluctuating but I was told it is not adjustable. If I use premium gas with octane booster it helps a tiny bit but for the most part it is very loud. Of course I can also feel a loss of power.

Monday, January 4th, 2010 AT 2:23 PM

2 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Was the knock sensor checked or replaced? What you described is usually caused by timing that is too advanced. The knock sensor has a role in where the timing is to be set. It tells the computer the exact point when a ping will begin. At that point, the computer is to retard the timing or keep it at that point. If it is bad, it can cause your problem.

Let me know if that was checked.

Joe

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Thursday, January 7th, 2010 AT 8:48 PM

JSMID

MEMBER
2 POSTS

The problem is now fixed. My intake gasket blew and all my coolant went into my oil. When my repair guy was replacing the intake gasket he noticed that one air port had been leaking air. This was a problem that we have been trying to pin down for two years. Truck is running super now. There is not even a hint of a knock or ping and it seems to have regained power. Yur mention of a knock sensor is the first time I have heard of one. My repair guy never mentioned this. Thanks, Jim

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