1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

Truck won't start, no spark

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Old 04-11-2015, 09:12 PM
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Truck won't start, no spark

I think I'm getting close to figuring this thing out. It's an 85 f 150, 302, manual transmission. Converted to DS2. The wiring engine harness I pulled from a junk yard had an electric fuel pump which mine does not, I was getting a short from one of these wires and disconnected them and solved that problem, but Now my problem is I can't get the engine to turn over, if I hotwire it from the solenoid I can, but not from inside the cab.so I've ruled out the starter, but even then I am getting no spark. I have already replaced the ignition switch, and the coil is also new. I took the duraspark module in (blue grommet) to test it, according to the tests, it's good. I also have a 3 connector yellow grommet module I tried with no success. What tests can i do to determine which components are getting or not getting power so I can figure out my problem? Headlights work, radio works, cab has power, engine does not, thinking I may need a different engine harness....
 
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Old 04-11-2015, 09:17 PM
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Turn the keyswitch to run. Then go out with a testlight, clip the ground lead to a good engine ground and then poke the + wire going to the coil. It should have voltage. Then poke the red wire going to the ignition module on the fender. It should have voltage also with the key in run.
 
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Old 04-11-2015, 09:30 PM
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Originally Posted by Franklin2
Turn the keyswitch to run. Then go out with a testlight, clip the ground lead to a good engine ground and then poke the + wire going to the coil. It should have voltage. Then poke the red wire going to the ignition module on the fender. It should have voltage also with the key in run.
I thought that red wire was supposed to have power! I didn't test the +coil but I did test that red wire (red usually being hot) i do not have power on the red wire
 
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Old 04-12-2015, 08:15 PM
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What would cause me not getting power there?
 
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Old 04-13-2015, 10:40 AM
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You have done a lot of wiring, so something was missed along the way I suspect. The module gets a full 12v when the key is in run and start. The coil gets a full 12v during start, but gets about 9v through a resistor in the run position.
 
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Old 04-13-2015, 11:40 AM
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Hm ok I'll have to trace some wires then, so where's the ground for that circuit? The spark plugs?
 
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Old 04-13-2015, 12:24 PM
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I traced the red wire through the fire wall to the ignition switch and from the ignition switch to the S terminal on the solenoid, should it be on the s or i terminal? Those bottom connections are a lot cleaner than they look in the pic btw
 
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Old 04-13-2015, 12:35 PM
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I tested the + side of the coil too and I do have power there
 
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Old 04-13-2015, 12:47 PM
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WOAH wait a minute wait a minute, I just noticed something! On the duraspark module, the red wire runs to the same plug as a white wire, HOWEVER on the harness side of the plug they are reversed!
 
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Old 04-13-2015, 03:09 PM
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The "crossed wires" has been noted, before. Somehow, aftermarket modules have these switched. It normally works, though [white to red and red to white].
 
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Old 04-13-2015, 05:30 PM
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Originally Posted by 1986F150six
The "crossed wires" has been noted, before. Somehow, aftermarket modules have these switched. It normally works, though [white to red and red to white].
Huh that's weird, I tried testing the white wire (harness white) and it sparked pretty good, dunno if I shoulda done that or not lol
 
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Old 04-13-2015, 08:23 PM
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Check the harness side red wire for voltage.

The "S" terminal on the solenoid gets the red/blue, that is for cranking and comes from the keyswitch by way of the neutral safety.

The red wire for the DSII box should go in to the ignition switch.
 
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Old 04-13-2015, 08:23 PM
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Check the harness side red wire for voltage.

The "S" terminal on the solenoid gets the red/blue, that is for cranking and comes from the keyswitch by way of the neutral safety.

The red wire for the DSII box should go in to the ignition switch.
 
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Old 04-13-2015, 10:41 PM
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Hmm, it must be something with the neutral safety switch then, I have it connected to the S, I have it connected to the ignition, and there's no breaks or anything, no corrosion, maybe there's some corrosion in the plug for the neutral safety switch
 
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Old 04-14-2015, 09:55 AM
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Update*** I checked the plug for the saftey switch and it looks ok, the saftey switch is in working condition, I'm gonna check out the plug that connects the under dash harness to the rear harness next, looked like there was some dirt down in the plug. Gotta be a connection or wire somewhere loose
 


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