cps rubbing on flywheel?

I picked up an 89 2dr 4.0 5 spd xj on monday for cheap that was running poorly. It would start and idle rough but that was about it. I took out the cps and drilled out the mounting holes a little and pushed the sensor closer to the flywheel and it started running good. I drove it to autozone to get some parts and when i went to leave it would crank, but wouldnt start. I pulled out the cps again in the parking lot and the end of the cps was rubbed to the point that there was copper wiring showing. I went back into the store and purchased a new cps and installed it. (it did not come with any sort of cardboard spacer and the bolt holes are a snug fit on the bolts, as in there is no room for adjustment). I made it about 1 mile down the road and it died again and would not restart. Got the xj pulled home and pulled the newly installed cps and it was rubbed through again. Im not sure what has gone wrong, is it possible that the flywheel is loose and is contacting the cps? did install it incorrectly? did i get the wrong cps? the new cps had about a 1/16in metal piece sticking down from the plastic housing that is now rubbed flat to the plastic housing. something else, there was never a plastic plug in the hole for the cps, is it required to be there to help space it?
any help is appreciated
Thanks

Shouldn't be happening. Do you have the factory shouldered mounting bolts or some generic stuff?

factory bolts...they fit snug into the cps mount with no slop

That's weird. I've got a photo that shows the clearance between the CPS and flexplate ring and there's a ton of room. Can't post it here though.

thats what has me thinking that there may be an issue with the flywheel, either warped or loose. Or i got an out of spec cps from autozone. the cps fits snug on the bolts and there is no adjustment up or down, the only way i could adjust it would be to put some sort of spacer behind the cps to move it further to the rear, which i dont think would help any. I was also under the assumption that the cps had a close tolerance to the flywheel to get its reading. Im lost on what could cause this

It's not a close tolerance. I wish I could post the photo. PM me your email address and I'll send the photo to you.

thanks for the photo cruiser...and i found my problem, the guy said he had just replaced the clutch in it and i guess he decided 3 bolts were enough to mount the tranny back. needless to say they worked loose and the tranny was shifting back and forth causing the flywheel to contact the cps. next question is does anyone know the correct length and thread pitch for replacement bolts for the bellhousing to motor?

I have a set of those bolts sitting on top of my spare transmission outside. Let me go measure them real quick.

EDIT: the E12 ones at the top of the bellhousing are 3/8-16 thread, 1 3/4" long under the head, grade 8. I suggest using a flanged head bolt or buying appropriate grade 8 washers.

The ones that go through the locating dowels on each "wing" of the engine block are 3" long, looks like 7/16-14 thread, grade 8. Would suggest flanged head bolts for these as well. The threaded section must be at least 1 3/4" long.

What idiot decided 3 bolts was enough to hold the trans on? That isn't the best move.

kastein said:

I have a set of those bolts sitting on top of my spare transmission outside. Let me go measure them real quick.

EDIT: the E12 ones at the top of the bellhousing are 3/8-16 thread, 1 3/4" long under the head, grade 8. I suggest using a flanged head bolt or buying appropriate grade 8 washers.

The ones that go through the locating dowels on each "wing" of the engine block are 3" long, looks like 7/16-14 thread, grade 8. Would suggest flanged head bolts for these as well. The threaded section must be at least 1 3/4" long.

What idiot decided 3 bolts was enough to hold the trans on? That isn't the best move.

Click to expand...

Thanks, thats exactly what i needed. The PO said he put a new clutch in it, so id say he was the last one in there. I only paid 400 for the jeep and it came with a 4.5in lift with full leafs (not installed) plus bunch of other parts (like roof rack, tube doors, push bar, etc) already on it. I honestly was getting it for parts and planned on scraping it, but now i think i may to try and save it.

Good deal then.

Damn, definitely a good deal, great even.

I would make sure the locating dowels are in place on both sides - they are steel tubes that slide into the engine block and trans bellhousing on each of the larger bolts at the block "wings". Just pull or loosen those bolts and make sure there is a sleeve by prying the bellhousing back a bit. If they are not there all sorts of wonky flexing/misalignment issues can arise.