Knock

JPEACE

MEMBER
1995 CHEVROLET CAVALIER
4 CYL
FWD
AUTOMATIC
103,565 MILES

The other day someone got my throttle stuck on my 95 cavalier. It was overrevved for about five minutes until they got it back and I got it unstuck. Now there is a knock in the motor. It sounds as if it is coming from the top in the head.I popped the valve cover off andd the rocker arms are looking like they r ok when I ran it. Any ideas

9 Replies

SATURNTECH9

MECHANIC
30,869 POSTS

Does it knock at idle or do you have to rev it to get it to knock?

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Monday, May 9th, 2011 AT 8:44 PM

JPEACE

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16 POSTS

It knocks at idle

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Monday, May 9th, 2011 AT 10:15 PM

SATURNTECH9

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Try this let it idle and start by pulling one wire off see if the knock gets lower or goes away. Then put the wire back on and move to the next until you have done all four wire's. If the noise gets a lot lower or goes away you know it's in the lower end not the top end.

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Monday, May 9th, 2011 AT 10:37 PM

JPEACE

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16 POSTS

Yeah it went away when I pulled the fourth plug

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Monday, May 9th, 2011 AT 11:29 PM

SATURNTECH9

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Sounds like you have a knock in the lower end most likely a spun rod bearing.

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Tuesday, May 10th, 2011 AT 12:57 AM

JPEACE

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16 POSTS

Could it be a valve that came unseated and slamming

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Tuesday, May 10th, 2011 AT 12:58 AM

SATURNTECH9

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If it were a valve slamming wouldn't it still slam with the spark plug wire unhooked and the cylinder not firing?The piston is still going up and down and the valve would still be opening and closing.

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Tuesday, May 10th, 2011 AT 1:09 AM

JPEACE