Now, I'm desperate!!! PLEASE HELP!!

I'm freakin here, folks!

I have a 90 XJ 4.0 that won't start. It IS getting fuel.

The coil tests good. I have replaced the CPS, and Dirtributor Cap and Rotor. I have tried a working ICM and a working ECM off a buddys 90 XJ. I have also switched around the relays. I have cleaned ALL the connector plugs I could find with contact cleaner.

NO JOY!! :helpme:

What am I missing? This is my DD and I gotta go to work tommorow morning.

Thank you for your suggestions!!!

Is it cranking?

If not, check the small green wire that runs from the starter and plugs into the power distrubution box. Mine just plugs in, with no clips. I accidiently knocked it out while working on the XJ, and sure enough, it wouldn't crank or even click. Plugged the wire back in, fired right up.

Have you checked for spark? First check by removing the wire from the coil to the distributor cap and holding that near a good ground. Have someone crank the engine and see if you have spark there. If so, then try it with a spark plug wire. If not, check for voltage getting to the coil.

No spark at the coil. I removed the coil wire from the coil and attached a circuit tester. There is NO spark. There is however current on the large yellow wire comming into the ICM.

It is cranking great...just no spark at coil.

see if the ground wires at the dip stick tube are connected. it seems strange that it ran one day and wont start the next.also check the wires at the base of the steering column at the ignition switch. sometimes they melt and you can loose power to the ignition circuit, cant hurt to look, anything is possible, but sounds like the pcm could have failed.

Check the wires (for burning and fraying) at the back of the intake/exhaust manifold, especially the CPS wires and the MAP wires. Check the harness that runs from the front of the fuel rail harness, down the front of the motor and under, too the temp. sensor, the knock sensor and the O2 sensor.
Check the connectors for bent pins and for connector poles that slipped out the back of the connector.
Check the five pole connector near the relay block, the big red cable, for current. There is a seperate fusible link at the starter relay for ECM, power.
Check the 30 pin for the latch relay, A/C relay front, latch relay second from front. Power to the 30 pin is also thorugh a fusible link at the starter relay.

A lot of possiblities, but a systematic test is the only way, unless you get lucky.