Posted my 89 Cherokee 6 cyl 4.0 problem a while ago and got some good advice. Have not had time to work on it until yesterday. To recap: no spark, truck was running and just stopped. After three hours sitting I was able to drive it home. Had a new cap and rotor, put that in. Now no start period. Pressure to the rail and you can smell raw gas when you crank. Took the coil to autozone and had them test it's ok. Took out plug #3 grounded it with an alligator clip/ pigtail to the body. Had the Ms. crank it no spark. Took the wires off the ICM got 14 volts to the plug in (small plug in Wire B, A is blank). Got 14 volts to a and B of the Three wire terminal also to the Tach drive C. Connections look clean but heard from auto zone the grounding can be a problem. Thinking of buying a small soda or bead blaster from Harbor freight to clean up the connections anyway. Taking the ICM over this PM they said they can test it.

My question: Could it be the top dead center switch? If so, can you check that with a continuity tester on a VOM. Or is that switch under power and you can test with a lamp. If you use a VOM and test continuity will it blip the meter so you can see that or is it too quick for a meter.

Second question if you disconnect the coil wire from the dist. Should you be able to read constant DC volts as you crank or will it simply blow the meter? If you can whats the volt range?

I am going nuts with this I'd take it to the shop but it's got to be towed and thats big bucks from where I am.

thanks for any help

Tom Kauffman

 

Went to an Autozone store with the ICM module as they can test. Module flunked. Autozone had a new one in stock, put that through the test you can certainly see the difference. Took it home, 5 min install Jeep runs great, as good as a 256,000/mile rig can run. Went around the block and the right front caliper locked up after sitting for two months. Great, I'm going to try and move the piston in and out a few times to free it up and if not back to Autozone. By the way the ICM was $115 and came with a lifetime warrenty which is really unusual for electronics they tell me.

Tom Kauffman