Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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Hi all, just bought my first Firebird. Its 84 With T-Tops. Anyway, the engine vibrates starting at about 1700 Rpm and get worse as the RPM goes up. Any suggestions on what to check?
Check your harmonic balancer first to make sure it is on securely. While the car is in park, let it idle and take a look at the harmonic balancer, see if it is wobbling side to side. If it is then time to replace the HB and see if I just had a guys 85 Z28 HB fall off and one of the symptoms is a bad vibration.
Originally posted by 86z/92rs: Check your harmonic balancer first to make sure it is on securely. While the car is in park, let it idle and take a look at the harmonic balancer, see if it is wobbling side to side. If it is then time to replace the HB and see if I just had a guys 85 Z28 HB fall off and one of the symptoms is a bad vibration.
Possible out of balance driveshaft? Does it quicken with engine RPM/speed? Perhaps the SB internals are shot? Anyone else? I know the late model f-cars with the stock steel driveshaft are prone to vibration at higher highway speeds, but is this happening, let's say, in your driveway?
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Dan Young
1995 Z28/M6
Groton, CT
You didn't mention if it vibrated only
while driving, or if the vibration occurs
even if you have it in park and goose up the
rpm's.
Mine did it only when driving, and it turned
out to be the rear axle tailshaft where the
driveshaft bolts up. Seems that at one time the clambs weren't tightened sufficiently
and the yoke assembly actually wore out.
I had to replace it.
...This is on a 9 bolt borg-warner, and of course the part was discontinued a long time ago. Thank god for the GM national parts
locator service =- Only cost me $75...
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89 Firebird Formula
ZZ4 Crate, WS6 package, 9 bolt rear, Hotchiss and Lakewood suspension
Edelbrock TES Headers, Random Tech 3" cat, SLP exhaust...
It happens in park and while driving so i ruled out anything past the tranmission. I also noticed that if I go full throttle from a stop there is a loud grinding sound. Could this be related to the vibration. Like the flywheel? Being the first car, I am not the most mechanicaly inclined (yet )So, Im sorry if I sound like I dont know what to check for. Thanks
)So, Im sorry if I sound like I dont know what to check for. Thanks 
