1998 Jeep Cherokee Sport, 4.0, 4WD

 

Could be the crank sensor, but thats just a guess. Is there a CEL or any codes?

 

Also a more detailed description of the problem would be helpful. Does it crank but won't fire up? Is it just nothing when you turn the key? Does it have power (interior lights, radio working)? etc. etc.

 

Sorry for the delay, PatHenry...Yes, it cranks but won't fire up and it does have power. When I turn the ignition, it "wants" to turn over but it seems like it's just not getting the gas needed to turn over. Thanks for your reply!

 

That's what I'm hearing a lot while searching YouTube, fb97xj1...I'm headed out to try and find the code now. Thank you!

 

Spray something flammable down the throttle body and see if it fires on it. If it does, it's fuel delivery related.

 

Thanks, Dave1123!


No codes come up when I run a guage check, fb97xj1. I was hoping something would show.

 

I agree with fb and Dave. Sounds like a CPS since you guys with automatics seem to be plagued by them failing (700k manual jeepin' and counting without a CPS failure - knock on wood... ). A bad CPS will lead to a crank-no-start condition as you are having, but you should definitely check for fuel delivery before "firing the parts cannon". A common symptom of CPS failure is that the Jeep will start and run when cold but kicks out when it warms up and then crank-no-start until it cools down and the cycle repeats. However it's certainly possible to just have it fail fully and then you get crank-no-start.

The CPS should be replaced with a Mopar part - the aftermarket ones are hit or miss with a whole lot more "miss". If you can't find a Mopar one, the distant 2nd place would be a Napa premium.

Before anything else, make sure you do your grounds and battery cable cleaning/tightening. It's free, easy and eliminates this as a possible root cause.
You should also check the fuses if you haven't and also make sure that your ASD relay is functioning correctly. Do a search on testing the ASD relay and you'll find plenty of guides for doing this.

 

Thanks a million, PatHenry...I will do just that! I appreciate your time.

 

I second the Mopar part! The CPS is a magnetic switch that senses windows in the flexplate or flywheel to time the engine's firing pulses. If the PCM doesn't see a signal, it shuts down the ASD relay, shutting off the fuel pump, ignition, and injectors. Mopar uses a neodymium magnet in it whereas aftermarket ones generally don't. A good strong magnetic field is essential to it's function. A new one would stick to a screwdriver. My old one wouldn't, but it was 230K miles old! Also, it has a paper wafer glued to the face of it that positions it the proper distance from the flexplate and this gets torn off on startup.

A good indication of a failing CPS is an occasional stall with an instant startup when you try. Sometimes you'll have to wait a couple of minutes before it will start. The shutoff is like you turned the key off, no stumbling. Mine got to the point where it would fire back up on it's own if it was still rolling! It did that twice while driving home with the new one on the seat next to me!

 

Hey all! Just thought I’d mention that the problem was my ignition coil. Hope this helps anyone who may have had a similar issue. Thanks for your help, everybody!