Wrapping up the 1994 ZJ 4.0L engine rebuild, water and oil done. Turn key and nothing. Engine turns over fine, but nothing. Sounded dead, pulled the coil wire and no spark. Everything worked fine before the rebuild, drove it into the garage. All wire seem hooked up, coil connector, distributor connector. It is a 5 speed manual, any ideas on what I may have missed.
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lost spark in garage
- Thread starter whiterice
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zukkev
Cornfuzzled yet again...
Is the crank sensor plugged in?
Co-Man-Che
Well-Known Member
A friend of mine had the same problem in his Cherokee, turned out to be the ignition control module. Unplug the three-wire plug going into the distributor, one of those wires should have voltage when the key is on. If you are getting power there, your ignition control module is probably dead.
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Bodaciouscj7
Well-Known Member
Another posibility is the ASD (auto shutdown) relay. Kills the coil.
I have been looking online a little and checked voltage to the CPS and that seemed fine, 5-8 volts going to the crank position sensor. Read up on the Ohm reading but didn't quite follow it. Also unplugged the coil and when I turned on the key, I am getting 13 Volts to the coil. Pulling the coil wire or a spark plug wire there is nothing. Zippo spark
skinny_pedal
Well-Known Member
Yes, it has been done many a time. always want to remove the CPS before pulling the engine.
I would say ignition control module. I had mine checked at autozone twice. Both test came up good. Put it back in and it ran for about 45 mins or so. Both times I took it back it gave it some sort of charge. Have them test it after you remove the coil. If it fires up after that I would say replace the 20$ cps. I replaced my good cps for another good cps. Cheaper way of checking always works for me. Plus you can pick up a icm for like 20$ with a coil attached. Do a search on here "cherokee won't start" should find it. I went through a few things
read in the Haynes manual on doing a voltage check on the CPS. Probe orange with and rotate engine with key on. I got the voltage swings of 4-5 volts at the flywheel passed the pick up points. So I am guessing the CPS is good.
zukkev
Cornfuzzled yet again...
From 0 to 5 volts, or between 4 and 5 volts...If 4 to 5 volts, CKP sensor is bad. And I'll second that you can damage the sensor while removing/installing engine; actually chances are pretty good... I've always removed it before engine removal, and installed it after engine installed...
I was using a analog volt meter and it showed more to the 4 volt then 5 volt. I went to A/Z and they sold me a single bolt application, maybe for a auto? I have a 5 speed ZJ. It has a 2 bolt CPS. So guess I will exchange it and try that.
Co-Man-Che
Well-Known Member
Did you ever find the solution to your problem?
