Pinging and rattle

JEFFERY A POTTER

MEMBER
BUICK ROADMASTER

I have a 1992 Buick, Roadmaster Limited with 56,000 miles. Under load at about 1400-1600 rpm a severe pinging sound immediately precedes a considerable amount of rattle. I use only premium gasoline, have adjusted the timing to 0 degrees BTDC, installed a new knock sensor, and a knock sensor control module. I use OEM parts ie. The spark plugs are AC Delco. The PCM returns no codes, but the noise is extremely disconcerting. I am afraid there is a problem in the valve train. Please, can anyone either confirm or dispell my suspicions? Thank you.

4 Replies

XOWEY

MEMBER
113 POSTS

Does it have good power?

If so, you could have a stuck closed EGR valve. :Wink:

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Thursday, July 13th, 2006 AT 11:02 PM

XOWEY

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113 POSTS

Another thing that can cause spark knock is temperature, is it running hot? Does it have a temperature gage? Does it only do it after it's warmed up? Is it getting good air flow through the radiator? Have you replaced the thermostat?

When did this problem start? Have you noticed this after fueling up one particular time.

Lots of things to concider here eh? We need a little dialog about this to find the proper direction. Don't get discouraged. :D
we can fix it! 8)

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Friday, July 14th, 2006 AT 8:56 PM

JEFFERY A POTTER

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2 POSTS

I replaced the radiator, intake manifold gasket, and thermostat about 2 months ago because the engine was running hot and I had noticed a coolant leak around the intake manifold. The 5.7 has great power and response, it now runs at 180-190 consistently and yet these confounded noises. Yes, I only notice the sound when the engine reaches operating temperature. If I understand your question: I use only premium gasoline.?

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Friday, July 14th, 2006 AT 9:17 PM

XOWEY

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113 POSTS

You said the keyword. Intake gasket. :Idea:

is it possible that you put the intake gaskets on backward? One end of the gasket has a small orifice or restriction in it. If you remove the thermostat and drain the coolant enough to look down the coolant passage and you see the metal gasket covering the passage into the cylinder head, we may have solved the mystery here. :Idea:

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Friday, July 14th, 2006 AT 9:42 PM