so my jeep just stopped running.started in the morning ran for a minute then died.checked for spark .nothing.I have 12 volts to coil but nothing coming out.I bought a new coil new cap and rotor and still no spark ? any help? next I thought was the pick up coil,yes ? someone must have gone thru this.Thank you

 

Do this.....http://jeep-xj.info/HowtoECUcodes.htm

 

My money is on....
A bad Crank Position Sensor
A bad Cam Position Sensor (aka Stator)
Dirty Grounds (All of Them).

 

ok so yesterday I bought a brand new distributor and still no spark ? anyone else ? this must have happed to somebody .

 

tried this did not work on my 1994 jeep Cherokee.

 

Here's the problem.

There are numerous things that can cause no spark.

You're not gonna find a Silver Bullet cure on the internet.

 

not looking for a silver bullet...looking for some help on all the places to look and check.....

 

See Post 3.

 

none of the above....??????

 

New CPS and coil and still no spark? Bummer...Maybe Crusers #4? >>


The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.

The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner and some fine sandpaper.

Squeeze the springy contacts closer together with some needlenose pliers. Bolt the coil back on to the ICU.

While you’re right there, unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier.

I feel this procedure should be performed at least once in the lifetime of a Renix Jeep.

　

Revised 04-04-2013
Attached Thumbnails

 

So you replaced the crankshaft position sensor? It is a very common cause of no spark on the 4.0. If you replaced it, what brand did you use? No lack of crap crank sensors available, especially on ebay. Be sure to verify that the wiring from the engine bay to the crank sensor is good.

Also try swapping the ASD relay in the PDC (black box under the hood) with another non-critical relay. These relays are all the same part number so swapping is not a problem.

Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995. (this procedure WILL work on your 94).

1) Start engine (if possible). Move transmission shift lever
through all positions, ending in Park. Turn A/C switch on and then off
(if equipped).
2) Turn engine off. Without starting engine again, turn
ignition on, off, on, off and on within 5 seconds. Record 2-digit
fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash,
4-second pause, flash, flash, flash. After a slightly longer pause,
other codes stored are displayed in numerical order. When MIL begins
to flash fault codes, it cannot be stopped. Start over if count is
lost.

NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.

 

thanks tj ill try that...

 

Here's some diagrams of the '94 ignition system. Hope they help.

 

Replace your ignition coil. I just went through this 2 weeks ago. I had 12v going into the coil and nothing going out. Replaced the coil and I'm back on the road.