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No spark

Posted: Fri Jul 13, 2018 3:14 pm
by mackdaddy
So two days ago, my jeep fired up and then died after about 15 seconds. It hasn't started since. I've narrowed it down to no sparks at the plugs. The plugs were pretty fouled with deposits so I replaced those. I replaced the distributor cap and rotor with still no luck. I replaced the ignition coil with no luck. When I got to the ignition control module, I pulled it off to find it had melted to the side of my jeep. I bought a new Prestolite icm and that did nothing for me. What am I missing? I just want to get my Jeep out of my work's basement at this point.


Has anyone here upgraded their distributor to a Motorcraft one? Is it an easy replacement that someone new to wrenching could handle? I've looked online for walkthroughs online and all the ones I've found are missing the images. Being still new, I'm lost without them and wiring worries me. Can someone point me in the right direction?

Re: No spark

Posted: Fri Jul 13, 2018 5:31 pm
by 440sixpack
I wouldn't call the motorcrap an upgrade.


In my opinion, and this will hurt some feelings, the HEI is the way to go. if you search you'll find plenty about it.

With the HEI you get a single wire hook up and you can throw all your other crap in the dumpster. it just plain works. you'd need new plug wires with it.


Out of the box my HEI ran like a charm, but I decided to put an American made Delco control module and a MSD gear in it. I don't know if it was needed but I feel better. I'd do the same thing again in a heartbeat.

Re: No spark

Posted: Fri Jul 13, 2018 7:07 pm
by mackdaddy
Is there a certain brand you recommend? What's required in an HEI upgrade? In my searches I came across junkyardgenius.com but a lot of the pictures and wiring diagrams are missing for my year jeep. I was just going to buy a MSD 8519 distributor at this point because I bought a MSD control module and coil to try to fix the original issue. I can always return them though as they haven't been installed. Maybe I can return some of the prestolite components I bought...

Re: No spark

Posted: Fri Jul 13, 2018 8:31 pm
by 440sixpack
HEI is the exact same system GM used for years . there are lots of brands available, Proform is the most expensive but I'm not sure they're any better. they're all made in China like everything else.

I bought a Summit brand one then upgraded it. I love it.


This is just one answer, there are other solutions if you like to monkey wrench.

Re: No spark

Posted: Fri Jul 13, 2018 9:17 pm
by Cecil14
The biggest issue I've seen/experienced with HEI is heat. Everything is in and under the cap, so you really need to watch heat dissipation. Use some decent thermal compound under the module in the distributor, and that will help the module servive a lot longer.


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