Edwin99Z

I was wondering if anyone could help me out with a problem. I just picked up my 99 Z-28/6 speed today and during the long drive home I started to notice a slight vibration in the lower RPMs. With further inspection and running the car through the RPM range, I noticed that the vibration occurred at all RPMs (it was the most noteable at 1000). It could also be found with the engine under load, or with the clutch in. My first thought is that the flywheel is out of balance, but I don't know how it would just get that way. The dealer that I bought the car from said that they replaced both motor mounts and the tranny mount. This made me suspicious so they threw in a warranty for the next 3000 miles. I need to pinpoint the problem so that I can get it fixed on their bill, plus I don't want to do anymore damage if it is the flywheel (I have been told that the LS1 relies on the flywheel's balance for its own balance. Any advice would greatly be appreciated. I can't start the mods until I fix it in stock form. Thanks.
Edwin

Damian

iTrader: (89)

You'll need to describe the vibrations a little more. Vibrating from the actual motor? Or chassis?

The LS1 relies on a Harmonic Balancer for balance, not the flywheel although a damaged flywheel can throw off balance.

Josh

Dustin Butts

iTrader: (5)

You said you just picked up your 99 Z...were you having some work done on it? If so, what kind of work? Need some more preliminary info please...

Edwin99Z

Sorry for being vague, I actually just purchased the car. It has 53K miles on it. I now am sure that it isn't in the drivetrain and it isn't quite a vibration, more of a bump. I think the problem is actually in the fuel or spark. The only other explanation is that one of the engine mounts is bad. The dealer said that they replaced both but I can't be sure until I get the car on a lift. I have never driven on a broken motor mount but I think that the problem would be worse at lower rpms (mine is worse at 1000) and as the rpms increase the pressure of the motor twisting would cause the bumping to decrease (assuming it is the right side motor mount). I was just jumping to conclusions with the flywheel and thinking the worst). Hopefully this info will help explain it

Edwin99Z

TTT anyone have any ideas?

SSEI

My 2001 SS does the same exact thing. I had a CF dual friction clutch put in and it felt like it was missing at about 1k and then cleaned up at higher RPMs. Switched clutch, went away. Next clutch, broke it in like a jerk and it is doing it again, wasn't doing it at first. I have to believe it is something related to the clutch, flywheel being unbalanced, improperly seated pilot, not quite sure but I am just living with it. I just switched my plugs and that didn't help at all. Sure would like a fix so here's a ttt