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Unread 05-04-2012, 08:19 AM   #1
Max121
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Join Date: Sep 2010
Location: Kenosha
Posts: 40
No spark help! 1995 yj 4.0

1995 4.0 Auto
I have replaced the CAPs in the ECM also have a 2nd ECM. Coil & CPS is new. Fuel PSI was tested all checks out. Grounds are all good and cleaned also add some to make sure was not grounding issue.

Seems when temp changes I have this issue. Was very warm and humid got cool over night seemed to be moister under the hood Cranks over just no spark.

Few times its started hard like timing was advanced but that has only happened a few times.

Never has a issue once its running and after 1st start seems no to have the issue again unless it sits over night or more.

I swap ECMs this A.M. did not help.

Could I (hot wire the coil) just run 12v to input of the coil to force spark?
Was also thinking maybe getting another CPS maybe new one was faulty?

Put a face to the crime


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Unread 05-04-2012, 08:56 AM   #2
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,608
Check your codes:
http://www.jeepforum.com/forum/f12/h...codes-1257145/


Hey Max. This is the deal. You need to see where you are getting power at in the system. You have a pickup sensor in the distributor that tells the system when to fire the spark. The first 2 things you replaced made sense but it looks like your pickup is bad. You can replace it by pulling the distributor and putting one in or they sell the distributor and sensor as a unit for around $80.
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Unread 05-04-2012, 09:59 AM   #3
Max121
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Join Date: Sep 2010
Location: Kenosha
Posts: 40
Que89YJ..
Thank you for the help once again! lol I will put a new pickup in tonight see what happens... Keep ya posted!
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Unread 05-04-2012, 10:14 AM   #4
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,608
Check the codes first!
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Unread 05-04-2012, 07:52 PM   #5
Max121
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Join Date: Sep 2010
Location: Kenosha
Posts: 40
There were a lot of codes lol I swapped the old ECM in after installing the new sensor everything seems to work great again.
Thanks for help you the man!!!!
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