It starts, runs for two seconds, and then shuts off as if the key was turned to the "off" position.

 

Put a test light or meter on the ballast resistor, or jumper wire if you did that, and see if there's power there when you fire it up.

 

grab a domestic power cord and rip the ends off

 

Test your CPS. If the PCM doesn't see signal for 3 seconds (or was it 2?), it shuts everything down.


EDIT: It's 2-3 seconds. Check this post.

 

If the CPS is dead it won't start.

 

having the same problem with my 94.replaced dist coil cps plugs and auto shut of relay,starts for 2 sec and dies...fuel pressure is fine,compression is fine.waiting for some one to come up with answer.keep posting and let me know if you fix your problem...

 

Sometimes.

 

I've changed out my CPS once already. I have read on here that XJs have a tendency to basically "reject" non-Mopar replacement parts. So even though the part is new and is working (it did fix the starting problem), the PCM isn't communicating with it? Does that seem plausible?

 

Never heard of "rejecting".

 

What I mean by that is that it still doesn't work like a Mopar replacement.

 

The aftermarket stuff is hit or miss. Bad out of the box is not uncommon.

Somewhere around here you'll find a procedure for testing it. Testing beats part swapping any day.

 

Alright, so I ended up grabbing a computer from a '94 (91-95 are compatible with each other). Disconnected the battery, unhooked the old computer, hooked up the new, hooked up the battery after 10 minutes, started up just fine. Problem solved. My computer was locked up like I thought before. Only $44 to fix this issue. Definitely go to a junk yard, pull a computer, and swap it. Even if it doesn't work, you could possibly have a good (used) computer should yours fail. But the problems you're having are what I had. And mine was a new CPS and computer.