Problem with 944 S

yellowperil · 07-13-2012, 06:38 AM

Nice car, one owner, well maintained, never beat on, no accidents. Now has picked up a nasty vibration through the shift lever at 3300 RPM in any gear up or down. Very noticable through shifter. First thought was exhaust too tight or touching somewhere. Seemed OK. This vibe can be felt, too a lesser degree, when reving the
engine with clutch in or out when going thru 3300RPM. Throwout bearing is quiet and seems to function normally. Axles are OK with maybe a little play, but shouldn't be causing this vibe as can be felt when not in motion. Trans axle is clean and dry but haven't checked fluid yet. We loosened then retightened all the exhaust and it doesn't seem to be the culprit. Motor mounts appear to be in a like new condition. Never looked at the transaxle mount but would it cause SOME vib when reving at stand still?
Anybody have any suggestions how to proceed. (selling the car notwithstanding) but wouldn't want to pass this problem on to next owner, Hope someone can help. Thanks

ivangene · 07-13-2012, 06:55 AM

Quote:

Originally Posted by yellowperil

Anybody have any suggestions how to proceed.

post your question in the 944 forum?

unless it has a flat 6 in it

bazar01 · bazar01's Garage

Quote:

Originally Posted by yellowperil

Nice car, one owner, well maintained, never beat on, no accidents. Now has picked up a nasty vibration through the shift lever at 3300 RPM in any gear up or down. Very noticable through shifter. First thought was exhaust too tight or touching somewhere. Seemed OK. This vibe can be felt, too a lesser degree, when reving the
engine with clutch in or out when going thru 3300RPM. Throwout bearing is quiet and seems to function normally. Axles are OK with maybe a little play, but shouldn't be causing this vibe as can be felt when not in motion. Trans axle is clean and dry but haven't checked fluid yet. We loosened then retightened all the exhaust and it doesn't seem to be the culprit. Motor mounts appear to be in a like new condition. Never looked at the transaxle mount but would it cause SOME vib when reving at stand still?
Anybody have any suggestions how to proceed. (selling the car notwithstanding) but wouldn't want to pass this problem on to next owner, Hope someone can help. Thanks

How many miles? Recent work done?

Vibration at idle is motor mounts.
Vibration at 3300 rpm could be
1. Balance belt jumped off a tooth when tension too loose.
2. Miss firing cylinder
3. Torque tube bearings going out

You are in the wrong forum though. You will get more responses in the 944 section.

crustychief · crustychief's Garage

I would check your belt. Mine did this a couple of hundred miles before I had to replace the cylinder head.

944 Ecology · 07-13-2012, 10:08 AM

What was the last job that was done before this symptom was noticed?

yellowperil · 07-13-2012, 10:19 AM

Last job was the new stainless exhaust in dec or jan 2012. Everything has been OK until just now.,, Put new plugs in this morning, no different. It also bucks a bit, that is, smooth transitions thru the gear seems not quite right. Altho, I might have always done that and now I'm more sensitive to these things. But the vib is for sure new and real. Once again thanks for any ideas.

944 Ecology · 07-13-2012, 10:30 AM

If that's the case, your most likely culprit is a problem with the balance shaft system. Make sure that the timing marks are lined up at TDC on #1.

After that, it's possible that you have picked up an imbalance in the clutch system.

Either of those problems will generate a vibration at 3000 to 3300 rpm.