low rpm - noise and shudder
 

So I'm driving home from Portland and my cardan shaft finally goes... there is lots of noise and serious vibration. I make it home and order a rebuilt shaft (and new flex disc) and installed them. Most of the noise and acute vibration is gone.. but there is still something not right and I am assuming unrelated to the shaft.

This is an rpm sensitive but not speed sensitive issue. Between 1-2k rpms going up or down tach there is a shudder.. sometimes with and sometimes without a detectable slight repetitive chirping or moaning.. the sound is of short duration and repeats several times. It doesnt seem to matter what gear and am in but shows up at low rpms.

One thought I have is the engine is shuddering due to the coils (which are original as far as i know) and this is causing something to vibrate and make a noise. I know this isnt a lot to go off of... but hey maybe someone else has has this happen and knows exactly what i'm talking about.

Any Ideeers?

My coils threw a CEL when they went bad. It wasn't a shudder either - the car ran like sh*t. It smelled like sulfur too.

Thanks D.
I have a feeling this isn't going to be an easy one to figure out...

Endless_corners....Did you figure this one out? I have a similar issue and I believe it is shaft related. I also had to replace my shaft not that long ago. Now the question is....did you use the special tool to position the centre bearing? I positioned my bearing by eye....and this may be the cause of the vibration.

Yesterday I re-positioned the centre bearing (once again without the special tool) and most of the vibration seems to have dissipated...but not all of it.

I know a lot of guys position the centre bearing by eye and have no problems, but I believe the tool is necessary to eliminate this type of vibration.

I believe the part number for the centering tool is 9680 or 000 721 968 00.

Interesting.. the shop I took the car to is not used to these cars.. IM SURE they just "put the part in". They really were SUPER reasonable price-wise.. but maybe not virgos. I didnt even know about "repositioning the bearing".. you are putting that on my radar.. because there is definitely some shaft-like vibrations remaining at certain speeds (torque/rpm levels or something). I thought perhaps this rebuilt shaft from vertex wasnt quite as true as my old one. But maybe I just need to fiddle with the bearing mount. I really appreciate the feedback mate.

Just jump under the vehicle and have a look at the centre mount. There are only 2 x bolts holding the bearing itself and the holes are elongated. You can move the angle of the bearing around quite a lot. Let me know how you go.

there are four bolts total though... right?

To re-adjust the bearing angle there are just two bolts! You don't have to undo the bolts that fix the mount plate to the chassis.

Brill thx!