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-   -   No Spark 1995 YJ 4 Cylinder (http://www.wranglerforum.com/f218/no-spark-1995-yj-4-cylinder-256879.html)

KenPlumlee 07-19-2013 10:35 AM

No Spark 1995 YJ 4 Cylinder
 
I have a 1995 YJ 4 Cylinder that is not getting spark to the plugs. Have changed the coil, distirbuter, rotor, and crank sensor. What is the most likely culprit?

kik 07-19-2013 10:52 AM

Usually when there's a no spark situation the Ignition Control Module is bad.

AllMudd 07-19-2013 11:14 AM

Quote:

Originally Posted by kik (Post 3980212)
Usually when there's a no spark situation the Ignition Control Module is bad.

Not always, the ECM can also go bad and cause this. I would suggest to the OP to check the fuses for the ign. There is one under the hood by the battery and one under the dash by the PB assembly. If these are good then I would check to see if you are getting voltage to the coil. Not to long ago another fellow Jeeper had an issue like this and it was the coil connecter one plug was falling out of the connecter and not making contact to the coil.

KenPlumlee 07-19-2013 11:25 AM

Quote:

Originally Posted by AllMudd (Post 3980287)
Not always, the ECM can also go bad and cause this. I would suggest to the OP to check the fuses for the ign. There is one under the hood by the battery and one under the dash by the PB assembly. If these are good then I would check to see if you are getting voltage to the coil. Not to long ago another fellow Jeeper had an issue like this and it was the coil connecter one plug was falling out of the connecter and not making contact to the coil.

Not sure how all of this works but should the coil have 12 volts to it any time the switch is on because it does not. I guess I need to read up on how the ignition works. I understand points and condensers but not much about electonic ingition. Guess that is what I get for being old.

AllMudd 07-19-2013 11:51 AM

Check the fuses

KenPlumlee 07-19-2013 12:03 PM

Quote:

Originally Posted by AllMudd (Post 3980428)
Check the fuses


Fuses are good but still no 12 volts at the coil

kik 07-19-2013 12:40 PM

Quote:

Originally Posted by KenPlumlee (Post 3980468)
Fuses are good but still no 12 volts at the coil

I'm still going with when this happens the prime suspect is the Ignition Control Module. I could be wrong but they seem to fail sooner than the ignition or computer module.

AllMudd 07-19-2013 01:43 PM

2 Attachment(s)
Here's some diagrams see if they help you out and check everything before either module.

AllMudd 07-19-2013 04:48 PM

Also according to my Chiltons book, you need to be checking for voltage while cranking the engine. Also try swapping out the auto shutdown relay under the hood by the battery with the horn relay.

KenPlumlee 07-22-2013 10:32 AM

Thanks very much. Will have to try it this weekend. Only have limited time to work on the project. Do you know what triggers the Auto Shutdown Relay to shutdown the spark and fuel?

AllMudd 07-22-2013 01:51 PM

Sure dont but from the looks of the diagram it only goes to the injectors, starter, and ign control.


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