I have little experience here, but I will share what I have. I ran into a similar problem with a friends YJ. There is a possibility that your ECU is going out. Dont freak out just yet, the usual culprits in this situation is a couple of $2 capacitors that can be replaced at an electronics repair shop for less than $100. I think if you search for "ecu repair" you may find your answer, or search, "cranks but doesnt start."

 

Well i cant get the coil off with the tools i have because there is an engine mount in the way. I'll get the wrench i need and try again tomorrow.

I can rule out the battery. I thought the idea might have some merit as it was kind of old, but i dropped a brand new one in and no change.

I'm really hoping its not the ECU. Even if it is an easy fix i try to stay away from the computer parts on vehicles. I can do mechanical work, but the computer control scares the hell out of me.

By the way...who said anything about a ford?

 

I've got the coil off and I'm checking the resistances, but I have nothing to compare them to. Here are the results of the tests provided in the haynes manual:

Positive Primary to case (set on high resistance scale 2000K ohm): no reading
Positive Primary to negative primary (set on low resistance scale 20 ohm): 1.4
Negative Primary to high voltage terminal (set on high resistance scale): 013

by no reading on the first test I mean that the display didn't change.

Should I replace it? or is it good? I'm going to leave it out until I can be sure because I know it will be a pain to put back in.

Thanks guys

 

I have an older ford pickup and it won't start if the grounds arent completely cleaned up. Sometimes jeeps are just as finicky.

 

Haha. oh ok. I know what you mean.

I took the coil to a friend who was able to test it and confirmed that it was good. at this point I know that the problem has to be in the ignition system, but what else haven't I worked on? aside from the ECU (and I really really really hope it's not) the entire system is either new or has bench tested good. My grounds are scratched clean and I can't find any loose connections. The jeep runs fine after it starts. I think that I'm just going to be running through starters (hooray for lifetime warranties!) and batteries if I can't figure this out. If you guys don't have any other suggestions i might take it to the *gasp* dealership and see what they have to say.

I want to thank all of you for your help. At the very least I got a really good tune up and some nice know-how

 

Have you checked and cleaned the connections on the starter solenoid itself? Should be attached right on top of the starter motor.

 

The starter and solenoid are both brand new. I haven't cleaned those connections because i figured they would be good coming out of the box

 

Oh. Well, my wires got really nasty once and she wouldn't crank, so I figured I would ask. Fired right up after disconnection and cleaning...

 

For some reason, I'm having a really tough time getting the male and female ends of the CPS connector disconnected. I'm sure that there's a simple trick to it, but it's not coming undone. I have a 2000 XJ. I've pulled, pushed, and tried to find the button that you push in to get the two to disconnect, but the connection doesn't look like anything that I've ever worked on. The Cherokee is apart, and I'm wondering what I'm missing.

 

I don't know how, but it finally came undone.

I'll provide pics of the project if I can.