HORRIBLE Vibration..

[slowchevy]

So my mechanic replaced my flywheel.. as it was cracked. How? No clue. But.. He sent me home with the car yesterday saying it had a misfire. All of the plugs have only a few thousand miles on them and he for some reason put brand new wires on. Well..The car isn't misfiring. I did a WOT 60-90 pull on the highway and the car drives normally. Performs like it always has.

So.. my question here.

If a flywheel / "flex plate" is installed incorrectly or not properly torqued down, can it cause vibration at any rpm?

There is also a "click clack"ish noise under more than half throttle and from what I heard, that's how you can tell if you have a bad flexplate ? Someone help me out with this.. thanks in advance~

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[bikrboy128]

find a new mechanic.

 

[slowchevy]

i will be after this is all fixed.

is it the flywheel do you think

 

[DarkShadow]

there IS a way to put it on wrong, the bolt holes can line up 2 ways, one correct one not. if its incorrect then its not balancing your crank right and it would cause a vibration. OR the torque converter needs to be rotated on the flywheel. both of those can cause a vibration.

 

[slowchevy]

it feels like the car is jumping around even at idle sitting in park.

could this be the rpoblem what you said, shadow ?

 

[MuffHugger]

http://www.youtube.com/watch?v=nC2gZMNkyJo

 

[bikrboy128]

it feels like the car is jumping around even at idle sitting in park.

could this be the rpoblem what you said, shadow ?

yes. the flywheel has weights on it, and it can only go on one way. that doesn't explain the noise though. maybe he didn't torque the flexplate to the crank properly, or torque converter to flexplate. it is really hard to say what a noise is over the internet. i would take the car back right away and tell him to fix his fuckup.

 

[slowchevy]

it sounds like a rod knock almost. but it isn't

 

[phat_ridegt]

yes. the flywheel has weights on it, and it can only go on one way. that doesn't explain the noise though. maybe he didn't torque the flexplate to the crank properly, or torque converter to flexplate. it is really hard to say what a noise is over the internet. i would take the car back right away and tell him to fix his fuckup.

x2 man

although i've been able to bolt it up a few different ways, there is only ONE way for that flexplate to be bolted to the motor. if it's messed up, or he didnt loctite/replace the bolts, it could easily cause it to come loose, or unbalance the motor like you are talking about.

either way, dont drive it

 

[Spicy McHaggiz]

Get a video of it. At least that way it can be told if its an injector "click" or otherwise.

Also, if there was a misfire, there would be a CEL. Doing a 60-90 run really doesn't prove much. And replacing the wires could always have an effect, and with the DIS system on the 3800's, its pretty easy for a coil pack to go out, and easier to replace.

 

[phat_ridegt]

there wont always be a CEL for a random misfire. if it is a dead miss, its more likely, but i have seen many cars not set a MIL, but throw a p0300 in history. one fault it sets, 3 faults it lights up, unless it reaches a certain misfire count

 

[slowchevy]

either way, dont drive it

i guess the fact i put 200 miles on isn't good then

 

[Turbocharged400sbc]

please tell me you kept the broken flexplate?

only other possibility is if they got a flexplate for a S1 3800...its the same bolt pattern as the SII but the service balance is different with the older talldeck 3800's

there's always the possibility of a bad mount causing excessive engine movement

 

[slowchevy]

the transmission mount and the two front dogbones and inserts were replaced with new units.

i didn't keep the broken one, i didn't think to

 

[slowchevy]

its at any speed. from sitting in park to highway speeds, increases with engine speed increase, a jumping up and down rapid movement, almost like a misfire but not. imagine having four out of balance tires at the same time a few ounces out, and thats what it feels like (but even then, sitting still in park.)

 

[phat_ridegt]

man something is def. wrong. take a long prybar, and pry on the motor somewhere, and see if it changes, if it does, its probably a mount issue, but if not, its either a converter, or flexplate issue. either way, take it back to the shop...

 

[DarkShadow]

also i had a loose flex plate sound like a rod knock.

eric, billboost installed his flex plate wrong on the 97 and his engine was moving around the engine bay at idle, hes got a vid of it somewhere

 

[DanJ]

Definitely need to find a new mechanic. Its unacceptable for them to give you your car in that condition.

 

[02BlueGT]

Yeah, it takes 10 minutes to do a good test drive.... you mechanic seems to be an amateur

 

[bikrboy128]

did you take it back yet?