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Topic Vibration or "pulsing" under hard acceleration |
Vibration or "pulsing" under hard acceleration grant - 7 years ago |
Re: Vibration or "pulsing" under hard acceleration MarcW - 7 years ago |
Quote
grant
Hi Folks,
I have an annoying vibration [mostly] under hard acceleration. This is in the track car, 2000 986S, 6-sp, PSS9s, stock motor.
It has existed for a while - although memory is never perfect.
Under acceleration i get a vibration through the chassis. My 2.7 street car (5-sp) does not do this, or not nearly as much. It certainly did when my motor mount failed..... As i recall they climb with speed (cant say if its better correlated to speed or engine RPMs, sorry). I have attributed it to several things - all possible, but hard to diagnose:
1. Out of balance or round rear tires - but its more than one set
2. Motor mount can be ruled out since i just replaced it with one from Pedro
3. Transmission mounts felt like this when they were replaced, but a) the trans mounts are only two years old, and b) they show no sign of leaking
4. Driveshaft issues, but i rebuilt them over the winter, they are tight, and slide smoothly in and out. I do suspect that the (normal) extreme angle they are at could contribute
This could all be normal operation in a car with lots of tires that are used very hard and therefore imperfect, ad is OLD (225k and climbing, lots of that track mileage).
If i see no sign of transmission mount leaking, can I rule them out?
If not, how shoudl i test? Apply pressure where and check for how much play?
Any other ideas?? -- especially from those who have chased similar problems on a similar chassis....
TIA,
Grant
Thanks Marc - comments below grant - 7 years ago |
FYI- ruled out tires grant - 7 years ago |
Recheck ... Pedro (Odessa, FL) - 7 years ago |
i wondered that too. Gotta get on a lift.... mount to frame or motor to mount? Thanks Pedro *NM* grant - 7 years ago |
So, i did more sleuthing grant - 7 years ago |
The vibration being near the engine resonance Laz - 7 years ago |
Another cause could be ... Pedro (Odessa, FL) - 7 years ago |
Hmmm - that's a plausable idea. Thanks. *NM* grant - 7 years ago |
I've long thought Boxsterra - 7 years ago |
Amazing diagnosis grant - 7 years ago |
Why do you dislike changing plugs/coils? Boxsterra - 7 years ago |