zeusrotty

iTrader: (1)

I am having issues with a vibration at 3k and 4k with the clutch in and with the clutch out. It is on and off but more often than not it does it. The car is an 87 Porsche 944 with a LS2 in it.
Do any of you guys have an idea on what this could be? This is the car...

409CISecondGen

iTrader: (2)

This belongs in swaps or maintenance...

gconnoyer

iTrader: (1)

In gear, out of gear, moving, stopped?

GTOSE

iTrader: (1)

Moved.

arthropraxis

Did you already see this post? http://944hybrids.forumotion.com/t13...ight=vibration

arthropraxis

Have you had any progress? I am still having the same issue. It may be the poly motor mounts on my car. What kind of mounts are you using?

TurboS10

iTrader: (12)

drive shaft angle

missing clip for u joint - I chased this for 6 months one time, cup moved half the thickness of the missing clip.

drive shaft balance

arthropraxis

These cars don't have the issue with the drive shaft angle. It is like the Corvette drive train using a torque tube going back to a transaxle. The vibration happens sitting still with the clutch in which rules out the drive shaft balance.
I don't know what the OP has tried, but I am out of ideas. The only option left is to get it street/dyno tuned to see if it is fuel trim related.
One interesting note is the Corvettes are hot balanced with the motor in the chassis. Anyone GM techs out there that are familiar with this procedure?
Thanks, for the suggestions. Keep them coming.

TurboS10

iTrader: (12)

No load vibration for me has always been fuel -lean spot. WB would show it. Local tuner might let you use theirs for a few minutes.

I've seen automatics with bad converter - but it was there all the time- took out thrust bearing though.
May have to pull the clutch and see if the vibration goes away.

Also check if the flywheel dowel is still there.

arthropraxis

I can't speak for the OP. I don't think at this point mine is the rotating assembly. I put on a new vibration damper and removed the flywheel/clutch/PP to have it checked for balance, it was balanced. The tuning isue is the only option that hasn't been tried. Would a street tune help? I have a mail order tune on it now.
Thanks, for the suggestions they are helpful.