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No spark until I let off the key - HELP

24K views 38 replies 10 participants last post by  natesms 
#1 ·
I have no spark at all, UNTIL I let off the key. When I left of the key it runs for a split second then dies.

I actually had this problem when I first dropped the motor in. I changed the wire to which my electric choke was hooked to and it solved it. No idea why though, but has had no problems since. It was running fine when I pulled it in the garage yesterday. Today I have this problem.

I have a brand new coil and ICM. Tried extras of both of those just to eliminate them. Have power to the coil the entire time, even when cranking.

I've jumped everything I know how to and I'm stumped. Anyone have an idea? I searched some on the forum and found one post with the same problem but no solution.

:whiteflag
 
#35 ·
i'll pull the dist cap & rotor and turn the crank the motor. but it was running before all this. the timing chain was replaced back in '04 with a dual cloyes. do yall think swapping in a davis unified igntion (dui) distributor from performance distributors would bypass all of these issues? it would take away the starting circuit/running circuit issue i'm having. all it needs is a single switched wire. the camshaft does the rest.
 
#36 ·
Yes thats fine but the QEM is a good unit your just having problems right now with it. On the other hand Bronco Graveyard has a GM HEI that is a drop in replacement for FORD SBW and BB that only needs one single 12VDC power wire to operate I'm thinking about one for my next toy. Before you do that what changes did you make before it wouldn't start you said it drove to where it is and it's still there.Look at anything you've worked with could be a loose connection or something forgotten. Did you check the power to the coil with your meter like I said before to see if the ignition is pulsing the 12volt to the coil thats what makes it fire thats why it pops when you stop cranking it. Then you look at the ignition module on the fender well and ignitor in the distributor. Have a good one let us know how it goes. ED
 
#37 ·
O one more thing make sure there is no metal stuck to the the face of the ignitor this would hold the switch closed and not let the flags do their job
 
#39 ·
Glad to hear you got it running again. I had the same problem where I tested something over and over again and it always seemed "good". One of the most frustrating things I've ever had to mess with for sure. hopefully we can help some other people out with this thread and save them the frustration! :banghead
 
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