Some Guidance Please
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Senior User
Joined: Feb 2013
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From: Southern Cal Desert
Some Guidance Please
I have had this problem with my '72 F250, 390. It has happened on a few occasions but has progressively gotten worse. What happens now is a complete interruption of electrical power to the truck. Before it happens with the radio on you can hear interference static (on the am side, still original radio) but then bang nothing. No headlights, dome lights nothing, zilch, nada. Wiggle the key, nothing. Then all of a sudden power is back! You can restart and go.
The worse one was coming home one night the truck was losing power, and it began to PING. I got it home but it ran rough and it was touch and go. Now its running fine again but scared to drive it. What should I be looking for? Battery is new and load tested and it is good. It does have an HEI dizzy but I can't see that knocking out power. HELP!!??
The worse one was coming home one night the truck was losing power, and it began to PING. I got it home but it ran rough and it was touch and go. Now its running fine again but scared to drive it. What should I be looking for? Battery is new and load tested and it is good. It does have an HEI dizzy but I can't see that knocking out power. HELP!!??
Fleet Owner
Joined: Dec 2009
Posts: 20,678
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From: NorCal
.. and install redundant grounds.
Besides the battery cables, the thick black wire with a yellow trace at the starter solenoid is what provides cab (and ignition) power.
Wiggle and jiggle that wire and verify its connections and connectors. Could it be pinched?
Besides the battery cables, the thick black wire with a yellow trace at the starter solenoid is what provides cab (and ignition) power.
Wiggle and jiggle that wire and verify its connections and connectors. Could it be pinched?
Logistics Pro
Joined: Aug 2015
Posts: 4,093
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From: Lind, WA- Eastern WA
After you "wiggle and jiggle that black wire W/yellow trace" follow it to make sure it's good the entire length. With everything shutting off, and then rrestarting (after a cool down period) I think it has to do with the circuit breaker inside the ignition switch. If you still have the older style ignition switch that has the round pin type connectors, check the pins and the wire connector for burn marks. If burn marks are there replace the switch with the new style (that has the flat blade type connectors). You'll have to get a newer style pigtail too. another thing to check; have someone start the engine while you listen to the starter solenoid. Any buzzing there? Make sure the solenoid mount is grounded well to the inner fender. I would disconnect the battery while not in use, until you find the problem-electrical fire=not good.
Hotshot
Joined: Mar 2013
Posts: 14,255
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From: Phoenix, Az.
How does your headlamp switch feel? You mentioned this happened at night. Notice the Black/yellow wire that Hio brought up. Follow it along and you will see before it reaches the ignition switch Ford spliced in a Black/Orange wire to power the headlamp switch. If your headlamp switch feels loose as a goose you might replace it. It may have an intermittent internal short.
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Since your running a HEI Dizzy, I don't know how you wired it into your ign. switch.
You should be using a #10 or #12 wire from ign. switch to the HEI dizzy unit.
Or are you using a relay to power up the dizzy with it full 12volts?
I'd check for any brown or burnt marks in the coil spring carbon button under the coil between dizzy cap & coil. Dielectric grease should have been a applied to the red rubber round seal. Also check that the carbon button spring it good. Also a good amount of Dielectric grease under the module unit to keep it from over heating, if over heating happens the engine will stall and you'll have to wait for it to cool before you'll be able to get it restarted again.
Then check all screws for the module and small connector wires on each end of the module.
If everything looks ok in dizzy then I'd make up a jumper wire and could unplug the dizzy an plug in your jumper wire an hook the other end to the plus+ side of your Battery. This will by pass your whole electrical system to isolate the problem an not in your dizzy system.
Orich
You should be using a #10 or #12 wire from ign. switch to the HEI dizzy unit.
Or are you using a relay to power up the dizzy with it full 12volts?
I'd check for any brown or burnt marks in the coil spring carbon button under the coil between dizzy cap & coil. Dielectric grease should have been a applied to the red rubber round seal. Also check that the carbon button spring it good. Also a good amount of Dielectric grease under the module unit to keep it from over heating, if over heating happens the engine will stall and you'll have to wait for it to cool before you'll be able to get it restarted again.
Then check all screws for the module and small connector wires on each end of the module.
If everything looks ok in dizzy then I'd make up a jumper wire and could unplug the dizzy an plug in your jumper wire an hook the other end to the plus+ side of your Battery. This will by pass your whole electrical system to isolate the problem an not in your dizzy system.
Orich
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