I have a 1993 Cherokee XJ 4.0 4x4 automatic. It was running great. On the freeway the motor just quit. No warning lights. Just stopped running and wouldn’t start. I towed it home and spent the last 2 days troubleshooting. Dash lights come on and the fuel and volts gauge work. The fuel pump runs. It’s electrical. No spark at the plugs or from the coil. I checked all related fuses. I replaced the coil because I wasn’t trusting my meter but now know the original coil and the replacement test fine. I ran the CPS check with the meter and it checks as okay. I pulled the distributor cap and contact cleaned everything. Not sure where to go with it. I read through a bunch of forums on this but usually they say check the CPS. I’m selling it and would like to sell it running. Any ideas?

 

A bad crankshaft position sensor will cause a no-spark condition and can test fine but still be faulty. It's the most common cause for a 4.0 to just die. Swap the auto shutdown relay with the fuel pump relay to check it too.

 

I replaced the CPS today and no change. There is barely any voltage to the coil when cranking. The constant side of the coil is staying at 12 volts with the ignition on. I assume I have an issue between the CPS and Coil which could mean the CPU. Anyone know how to run diagnostics on a 1993 Jeep Cherokee CPU.

 

A bad Auto Shutdown (ASD) relay is the most common cause. Swap it with an identical relay in the power box, like the fuel pump relay, and test again.

 

I should have mentioned I tried switching the ADS and fuel pump relays. Still got the fuel pump activating but no spark. I appreciate the help but I’m throwing in the towel. It is for sale not running. I got what I wanted out of it. Cheers!

 

Fair enough. Sometimes you just have to walk away. Hope the next project is a smoother one. Cheers.