cranks but won't run

Hi folks,

New here and have been reading a bunch of posts. I like the help offered and decided to join and see if someone could help me(my bronco).

I have a '72 with a 302 and Duraspark. I took it out for the first time the other day after over a year of rebuilding. It cranked right off, ran for 20-30 mins. at the house fine so I decided to go for a ride. Left home and all was good. About 5 miles later I noticed smoke from under the hood, pulled over and shut the motor off. Turned out nothing major, line to oil pressure gauge too close to header( my fault for not double checking everything before leaving). I had a spare with me (how I don't know) and repaired it. Ok, here is where the problem begins. When I tried to start the motor again all it will do is turn over. It does fire up but dies immediately when the starter disengages. As long as I keep the starter engaged it runs. I've been through my wiring and can't find anything loose, disconnected or broken. Oh, I forgot to mention I converted it to an ignition switch and push button start. From what I have read it seems to be a wiring issue but could this be a ICM issue?

Thanks in advance

Hi, welcome..!!

Initially & off the top of my head.., assuming you have it back home.., turn the key to "on"  & see if/what voltage

you have at the + side of coil. If memory serves.., the Duraspark starts on 12v & runs on 12v.

Yes, the modules can (& have been known to) fail.  So can the coil, as well as the pick-up coil inside the dizzy.

The ignition switch has a start and a run connection.  It sounds like the run connection is not hooked up.

This diagram is from a 1983 Bronco Duraspark II ignition and should be very similar to yours.

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I just had this problem. Check the resistor by the passenger firewall. I was getting voltage at the coil and spark, but had the same symptoms as you. When I tested the resistor and moving the wires the resistor broke the rest of the way,

Warning, the ICBM that Auto Zone has in their system as of a couple weeks ago is wrong. They tested mine and it failed. I got the new one and the symptoms got worse. That's when I went to the resistor. Long couple of days researching. I reported it to the zone.

Hope this helps.

Thanks for the suggestions. I went over everything again this past weekend. I found a blown fuse on the ignition changed it and it blew again, again and again. I pulled the ignition control panel off replaced the fuse and it didn't blow the fuse again. It did however ***** up my ICM. I replaced it and everything runs like it was supposed to. I had a short from the panel to the dash that has been fixed.