Electrical woes
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
With the ignition switch in the run position, and the 4 pin connector disconnected, there should be battery voltage at the (+) terminal of the coil. There should be nearly the same voltage on the (-) terminal. If not disconnect the coil wire from the coil, and check again.
If the (-) terminal has close to battery voltage, turn ignition switch off and reconnect the 4 pin connector. Check the (+) and (-) terminals on the coil again with the switch in the run position. There should be battery voltage on the (+) terminal, or 6 volts between the (+) and the (-) terminal.
Let me know what your readings are.
If the (-) terminal has close to battery voltage, turn ignition switch off and reconnect the 4 pin connector. Check the (+) and (-) terminals on the coil again with the switch in the run position. There should be battery voltage on the (+) terminal, or 6 volts between the (+) and the (-) terminal.
Let me know what your readings are.
Thread Starter
|
Elder User
Joined: Jan 2004
Posts: 867
Likes: 0
From: Eastern Pa
Well after lots of testing and following many of your advice I decided to take the pickup coil back to Autozone. They said they could check the module. When I got there they all said "who told you we can check the module?" Well they looked up a thing or two and found some instructions on their computer and all they did was use an ohm meter to check resistance through the module. It should have read between 400 and 600 and it read nothing. They pulled out a new one and checked it and it registered about 460, so I brought the new one home and voila, it works. I only hope it keeps working now. I wonder if other manufacturers check theirs in a similar manner. Thanks for your help.
Cargo Master
Joined: May 2003
Posts: 2,561
Likes: 1
From: Earth
Glad you got it fixed. Mine had the same symptoms yours did when it went. Only I hope you didn't get stranded beside the road......like I did. Funny thing is, I left the truck on the road, had somebody pick me up, and we went straight to NAPA to get a new module. We got back to the truck and it started right up.......with the old module in it. Anyway, I got it back home, replaced the module and now 8 or so years later, it still runs great. 
Lead Driver
Joined: May 2004
Posts: 5,040
Likes: 137
From: Maryville
After our year long engine build and putting the front back on we had starting issues on our 78 F-150 4x4, volt meter showed the coil was getting 4 volts. I removed the ign box, plug was busted, so getting it tested was fun, had to ID the wires to plug them in, inconclusive, so I replaced it, no change. The coil hot comes from in the cab, there is a disconnect point near the brake booster for the coil wires, trace them back and pull out of the loom, you'll find it. When pulled apart we found it was very corroded, limiting the voltage passing through, was hard to clean up, but immediately fired up when it was back together.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
I thought it was the module, but I wanted to get the other tests to be sure that it wasn't something else. It is good to know that the module should read between 400 and 600. If I knew that earlier, I could have told you to do that first.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Laughing Gas
Joined: Aug 2004
Posts: 964
Likes: 1
From: Roseburg, OR
I went round and round with something similar last Spring when I was finishing putting my 400 in my F-100. My Napa store had a diagnostic machine that they could test the Duraspark module with and it tested bad, so I got a new one. I had already purchased a new pickup module from Carquest months prior when I was getting parts for the motor, so I figured that was good. Put in the Napa module went to fire it up, fired okay. After I got everything buttoned down, I went to fire it up to do the cam break in... nothing. I spent hours tracing back through my wiring, could find nothing wrong (and had to destroy the nice tape job I had done on all of the harnesses I made).
So I took the module back... it tested bad. Got a new one. Nothing. WTF?!!!!! Finally found the test for the pickup module, it tested borderline on the low resistance. So I replaced it, everything has been fine since.
So I took the module back... it tested bad. Got a new one. Nothing. WTF?!!!!! Finally found the test for the pickup module, it tested borderline on the low resistance. So I replaced it, everything has been fine since.