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-   -   No spark (https://www.cherokeeforum.com/f2/no-spark-201382/)

jon_89 Nov 2, 2014 05:42 PM
No spark
 
As the title says I have no spark on my 87 xj with 4.0. I recently replaced plugs cap and rotor. It ran fine then it sat for a couple weeks and then no start. Checked cps and it tested bad so I replaced it. Still no spark again tested cps and it is only putting out .3 vac not the .5 vac like it should. Well I replaced it again and still only at .3vac. I took the coil and icm in and they both tested good. Where do I go next? Is it possible to get 3 bad new sensors?

JeepMN Nov 2, 2014 05:49 PM
What type of sensor are you buying?

Only replace the CPS with a Mopar factory replacement. It costs a little more but our jeeps do NOT like those aftermarket sensors.

hicj7 Nov 3, 2014 04:12 AM
Something simple? Fuse?
 
You may have already checked this, but I believe there is a ECM fuse somewhere. Probably in the fuse block under the hood. Ive been burned by this once. Is the coil getting a signal? I imagine there is a way to test the coil...
Sorry not more help

cruiser54 Nov 3, 2014 07:54 AM
Originally Posted by hicj7 (Post 2966540)
You may have already checked this, but I believe there is a ECM fuse somewhere. Probably in the fuse block under the hood. Ive been burned by this once. Is the coil getting a signal? I imagine there is a way to test the coil...
Sorry not more help
No fuse for ECM.

OP, click on my link below and read Tip 7.

Would never hurt for you to do Tips 1,3,4, and 5 anyway.

jon_89 Nov 3, 2014 12:46 PM
I'll try drilling out the hole and see if that helps

cruiser54 Nov 3, 2014 03:12 PM
Originally Posted by jon_89 (Post 2966755)
I'll try drilling out the hole and see if that helps
I would to the 4 Tips I suggested first. Take about 45 minutes.......

jon_89 Nov 3, 2014 04:35 PM
Okay went through refreshed all grounds cleaned connections and still only .25-..3 vac from cps. Do you think it could possibly the flex plate not spinning fast enough? I have

jon_89 Nov 3, 2014 04:35 PM
Okay went through refreshed all grounds cleaned connections and still only .25-..3 vac from cps. Do you think it could possibly the flex plate not spinning fast enough?

jon_89 Nov 3, 2014 04:36 PM
I haven't drilled the holes yet.

cruiser54 Nov 3, 2014 06:15 PM
Originally Posted by jon_89 (Post 2966909)
I haven't drilled the holes yet.
Drill only the upper hole per the instructions.

Did you do Tip 4 yet?

jon_89 Nov 5, 2014 08:58 PM
Gone through did tip 4 and drilled the upper hole to 3/8 for a stronger signal. Now I'm getting .3-.35 vac which is more than before this leads me to believe I might be getting weak magnets. I'm at a complete lose.

djgrayxj Nov 5, 2014 09:18 PM
Originally Posted by JeepMN (Post 2966148)
What type of sensor are you buying?

Only replace the CPS with a Mopar factory replacement. It costs a little more but our jeeps do NOT like those aftermarket sensors.



Note from DJ
You didn’t answer JeepMN question this is important information!

cruiser54 Nov 5, 2014 09:20 PM
Originally Posted by djgrayxj (Post 2968611)


Note from DJ
You didn’t answer JeepMN question this is important information!
Yup. If all else fails, get the PC307 from RockAuto and drill it per the instructions.

jon_89 Nov 5, 2014 09:33 PM
Sorry forgot that. I've bought 2 from napa and one from orielys


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