I replaced the flexplate in my 88 cherokee. Then it wouldn't run for more than a few seconds and would not accelerate. I imagine that, while putting the transmission back in I damaged the CPS. I bought a new one and installed it. I tried to start it up and nothing. I checked the CPS again and it was broken, the flexplate hit it. It was the correct part so, now I am at a loss. It doesn't seem like a shim would help in this case. Any suggestions?

 

Where did you buy your crank sensor?

If it was an aftermarket, buy one directly from Jeep.

There are lots and lots of threads of issues with aftermarket crankshaft position sensors.

Paying a bit of extra money for the OEM sensor here is money well spent.

 

when i installed mine on my 89 it just touched the ring gear i removed it and filed the magnet a little worked ever since

 

Do you have the right flexplate in ? The metal pick-up on the newly installed plate might be larger and hitting thr CPS..

Anytime we changed a flywheel/flexplate we would always match them up -brand new or not just to make sure. Sometimes a new flywheel would come in as a replacement and be sooooo wrong it wasn't funny.

 

I got the sensor at Napa and the flexplate from Rockauto.com. Everything matched up with the old parts. The new flexplate didn't hit the old sensor, I damaged the wire coming out of the sensor during install. I will try to locate an OEM sensor.
I'll keep posting as this plays out
Thanks for helping out a Newbie

 

Couldn't locate an OEM CPS but, the nice folks at Napa were kind enough to take the broken sensor back. After much head scratching and 4 letter words I decided to pull the trans again. I found that the new flexplate had gotten damaged and had a bump on the ring that the CPS reads. I assume this happened during install but, could have happened when the new sensor hit the ring. I now need to order a new flexplate and a new sensor. UGH!!! Any tips on how to prevent this from happening again? My Haynes and Chilton manuals are pretty useless at this point.

 

I'll assume you have either taken out the trans OR moved it back far enough to get at the flexplate bolts--YES/NO ?

 

The transmission is out.

 

Make sure the converter is ALL the way back into the tranny. Leave the CPS out for now. Really make sure that the new CPS and the flexplate are matches so u don't do this again. the trans should just basically go right on the 2 locating dowels allowing u to get some bolts in. Tighten them up snug and see if you have some clearance between the flexplate and converter -u should have to POP to converter forward to the flexplate maybe 1/4" or less but the converter should spin free. then line up ur flexplate bolts and the converter. after tightening all the trans bellhousing bolts. The reason I would leave the CPS out for now is so u don't damage it on the install they are easy enough to change even when fully assembled.

Just don't force anything --if you have try to hard something is not right and take a good look at whats up. I have seen vacuum lines get caught up top for example and screw things up just that easy. take ur time and do it right.

You can PM me if u need to.

 

there are some good threads about getting ur tranny set up converter wise and a utube video --I'm sure search will bring up many..GL

 

I figured what I did wrong with the first install and it is now up and running. Now instaed of the flexplate noise there is a strange grinding noise coming from the front or middle. The grinding noise happens at idle both in and out of gear and then at its worst when I start off in forward or reverse esp if the wheels are turned. To try and narrow it down by taking the front drive shaft is out. No change. I thought it was stuck in 4wd...guess not. The output on the transfer case does move without the driveshaft on in 2wd but I can stop it with my hand. I can feel it in the drivers floor pan but, hard to say if it can be felt from anywhere else, as I can only drive from one place.
I also removed the wheels and made sure one or both calipers weren't hanging up...wasn't that. Should have known bc it does it at idle in Park.
This Jeep has a new engine, new flexplate.
Is it possible the hubs are half engaged? Partially stuck in 4wd?
This problem wasn't there before I changed the flexplate and the flexplate noise would not have drowned this one out.
I would appreciate any help anyone has.
Thank You.