So my '99 I6 4.0L Cherokee died on the road a few weeks ago...just kind of sputtered out and wouldn't restart. It would crank and crank, just no turn over. I had a shop check it out and the diagnosis came back as a bum PCM--$1000 bucks! I got one programmed from a company on line for $200 and did the 4 minute install myself...still no luck. I think I have fuel (Schroeder valve on the rail spits, but I don't have an actual pressure gauge; also I can hear the fuel pump priming when I click the key to run). The shop that diagnosed the PCM claims to have tested the Ignition Coil and CPS with no problems, but those are the only other things that I can think of that will keep an engine from getting spark...

If anyone can think of something I'm missing, I'd be very grateful for a little insight/advice. I figure CPS/ignition coil are going to be the suggestions, but was just wondering if anyone had seen these probs and can help me out. Many thanks in advance!

 

My brothers 96 did the same thing. We where driveing on the highway and it just shut off. We where told temp sending unit and crank angle senser. Changed both and have'nt had a problem since.

 

CPS.... My ZJ did the same thing. Replaced and fired right up.

 

thanks for the input, fellas. i replaced the ignition coil today and it had no effect...on to the CPS next, i suppose. thanks again for the responses

 

1. Buy a can of starting fluid and see if the engine starts while spraying into air intake.
2. Borrow a timing light and check for spark.

 

thanks, dennis. I took for granted that the shop I paid for the original diag would have done this, but I clearly need to double back and cover all the bases. good, thoughts, thanks for the input

 

so after chasing a ghost it appears, i got the truck running today. checked the spark in the #1 cylinder and got nothing so i replaced the plugs and wires and went ahead and got a new cap and rotor as well. noticed that the wire from the cap to the ignition coil was looking rough, so replaced that too. viola! fired right up. don't know if there's another problem lurking...might just swap out the CPS before it goes bad.

thanks again to everyone for the input!

 

[QUOTE=spoons;1375983] ...might just swap out the CPS before it goes bad. ...QUOTE]

That's a great idea!
I replaced my CKS at home in my driveway on a warm sunny day, much better than waiting for when you're knee deep in mud 40 miles from home!

The CKS is underneath on the flywheel/bellhousing, CPS is in the distributor.

The top engine stuff, temperature sensor, TPS, can wait.
My O2 sensor in the exhaust pipe is not needed to start or run, so that only gets replaced when broken.