Codi Patterson

I have good compression good fuel pressure replaced distributor plugs plug wires cps throttle body sensor checked timing chain. It starts right up but runs really rough has bad backfire. All happened after I replaced the clutch and flywheel. It’s been downhill from there. Buddy was leaning towards ecu

PatHenry

Did it happen DIRECTLY after replacing the flywheel??

If so, I would suspect that the new flywheel was not correct and it's getting bad readings from the CPS... what kind of replacement was it?? Original manual flywheel to aftermarket new? Original to used but better original?

Edit--- I'm sure it's not the answer you want to hear, and I obviously am purely speculating, but my "gut-feel" on a "I replaced my flywheel and after the engine ain't running right" situation is going to result in having to pull the tranny off again to correct.

How and why did you replace the flywheel?? The flywheel is super precision balanced, it needs to be installed correctly (with little room for error), you are supposed to use new bolts and they aint cheap or hardware store type bolts.... lots of room for something to go wrong.. looking back, is there anything that you may have not thought much about at the time that might have been a potential concern?

lawsoncl

All the amateur mechanics are quick to blame the computer, but it's rarely bad.

It's more likely that it's the wrong flywheel, a poor quality flywheel, or you damaged the CPS sensor or wiring by not removing it prior to separating the trans and the engine.

Codi Patterson

I replaced the flywheel when I was changing the clutch, and the flywheel had heat lines and check marks, but I didn’t think to beyond on the flywheel I got, thought they were mostly the same For this year, I used the original bolts I took out. And I used my impact. As well looking back might not of been a good idea
and yes ran great then dropped tranny and put it back and boom

Codi Patterson

I replaced the cps and I got the flywheel from orileys

PatHenry

IIRC the FSM has a very specific torquing procedure for the flywheel.... I'd download it for your year and check... cruiser54.com or xjjeeps.com aught to have it for free download.

It's gotta be an issue with your flywheel... probably a minor but important difference in the "nodes" that the CPS uses and/or installation error.

Do you have the old flywheel? Any chance you could clean it up with an emory cloth and reuse it? I have heard of folks reusing the bolts and being OK, so that may or may not be relevent.

PatHenry

Did you get a new Mopar CPS? I might try reusing the old one if you still have it before pulling the tranny again if it's aftermarket... I've never replaced a CPS on a manual jeep... never... and that's over 400k miles on a 94 xj, 300k miles on a 00 TJ and 50k or so on a 95 XJ.
I firmly believe CPS failure is a plague of automatics and only automatics due to the higher heat generated.

Codi Patterson

ok I’ll check that out and yes I have the old flywheel. Was gonna have it resurfaced before I bought the aftermarket one. But bought it instead.

Codi Patterson

will do I’ll put the old one back on and yeah it was just a 20$ cheap sensor I got