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Discussion Starter · #1 ·
I have a 79 bronco with a 429 my problem started with the rad I changed it fired it up then shut it off and now it has no spark I have changed the ignition box and the coil but there is no juice getting to the coil tested the box it works but nuthing at the coil.I'm thinking about updating the whole ignition system was wondering how hard it is?
 

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had a similar problem about a year ago.....truck would run fine a while then shut down suddenly.turns out one of the two coil wires had a spot with no insulation and was grounding out on the manifold.check all ignition wires for cracked or missing insulation and also make sure everything is grounded good.....the factory ignition, when working properly, is pretty reliable.
on a side note.......i bet that 429 moves that beast along pretty good huh?:popc1:
 

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It could also be the resistor wire under the dash burned open. Easy to do a visual check, it'll be the larger wire, either gray or orange, with RESISTOR printed on it.

Try starting it in both neutral and park, and jiggle the shifter when starting. That might tell you if it's the neutral safety switch.
 

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Check for Power at the red/grn wire coming out the back of your ignition switch with the key on. If you don't have it there, it's in the switch, if you do, it's wiring between there and the coil. The neutral safety switch won't effect this problem as mentioned before, that would only prevent the starter from energizing.
 

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Discussion Starter · #8 ·
Update: changed ignition switch (not the problem) tested voltage to coil only .6 volts on + side if i disconnect the distibutor wires at the plug I get 9 volts at the coil still stumped?
 

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Update: changed ignition switch (not the problem) tested voltage to coil only .6 volts on + side if i disconnect the distibutor wires at the plug I get 9 volts at the coil still stumped?
Nine volts on the positive wire is what it should show, after the voltage has been reduced by the resistor wire.

When you changed the coil, did you reinstall the RFI condenser that's attached to the coil? If so, disconnect the condenser wire and then try starting it......

The only other possibility would be the pick-up coil inside the distributor shorted to ground.
 

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The fact that you only get .6 volts then it goes to 9 when you disconnect the dist points to a bad pickup in the dist. I would change that next. If it still does not start....
If you have the horseshoe connector for your coil, check the terminals for corrosion.
I agree dissconnect the condenser to see if its pulling your voltage away
When starting the coil will have 12volts (comes direct from the solinoid) then in run reduced voltage. You might want to run a jumper wire from the Pos + battery terminal to the coil and test for start.
 
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