90944

Did you ever find the issue?

nothingbutgt3

I had the same issue in my mint 96 carrera and it didn't make this issue (noticed it like a sound, like if a drive shaft was eccentric...but only between 1800 and 2000 rpm) when idling, but only with an engaged gear, especially an higher one, with throttle load below 5% and if driving on a street in false floor uphill, even more.

I made myself this idea, accross many years, that it was the DMF to generate the issue...

While in 1st, 2nd or 3rd gear, even though the throttle is only slightly open, the low gear makes the springs inside the DMS be fully compressed...even at the 1800-2000 rpm that are known as the resonance rpm for our engines, that's why they installed the DMF, to bring those resonance vibrations below idle...but probably if the springs of the DMF aren't elastic anymore, this effect gets reduced and in the same rpms arrive bit of intermittent vibrations.

The inertia of the car in 4th and 5th gear allows the car to go with a very slight load, so much that at some point the wheels carry on the clutch at same speed of engine crankshaft and there is a very few torque that need to be transmitted to the clutch from the second plate of the DMF...in almost a lack of forces, the spring, due to the vibrations arriving from the engine, starts to have a resonance.

I am not able to explain this in english, but it is an effect linked to the dragging of the car.

Infact, when i changed the DMF and clutch, it disappeared, but after 20.000 km it started again, very mildly, I must say.
I think the way to avoid it is by installing a single mass flywheel.