Electrical short
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Electrical short
My ol truck like many has a modified electrical system. A couple weeks back the sound from my radio started cutting in & out, but the power would hold. Next the truck started shutting down. I noticed the tach went to zero. A couple times it didn't want to start after being parked. That so far has been the hardest to overcome. Jiggling wires under the dash has worked so far to get it restarted. I haven't been able to spot anything yet, any ideas, ground or hot?
Right now the radio seems to be holding.
John
Right now the radio seems to be holding.
John
Postmaster
Joined: Nov 2001
Posts: 3,351
Likes: 1
From: Escondido, CA
Yeah. Blue's are the better ones.
John the fuse block attached to the headlight switch or the firewall pass through could be causing a few head aches. But it could be anything at this point without seeing the overall condition of the wiring harness' and whether you did the Dur-A-Spark swap.
John the fuse block attached to the headlight switch or the firewall pass through could be causing a few head aches. But it could be anything at this point without seeing the overall condition of the wiring harness' and whether you did the Dur-A-Spark swap.
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Thanks for the replies, nothing has been changed in 2-3 years, I am running a Unilite Dist. that has been in there for a while.
After the post this morning, when I went to leave the speakers were cutting in & out terrible so I shut the radio off. I drove about 20 miles to do a job today no problem with running, drove the truck 6 block & back at lunch, radio & engine working good. This afternoon when I got ready to head home, the radio was playing good, and the truck shut off after 20 ft, didn't want to re-start. I patted the wires up near the firewall a few times and it fired up and no more problems to home.
John
After the post this morning, when I went to leave the speakers were cutting in & out terrible so I shut the radio off. I drove about 20 miles to do a job today no problem with running, drove the truck 6 block & back at lunch, radio & engine working good. This afternoon when I got ready to head home, the radio was playing good, and the truck shut off after 20 ft, didn't want to re-start. I patted the wires up near the firewall a few times and it fired up and no more problems to home.
John
Elder User
Joined: Oct 2009
Posts: 825
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From: Dallas, Texas
John,
You've helped me on several occasions, but I am not sure I can help you very much here.
My thoughts are the sound from the radio is not "cutting out", but the radio is losing power intermittently. The tach going to zero would also indicate some type of a pulse loss since it is wired back to the coil (-) terminal. It would seem this intermittent loss of power (maybe at the coil?) might account for the truck being hard to start at times or having the engine unexpectedly die on you. If it is a loose connection, then the truck might then be able to then be started simply by touching the right area.
My best guess is to double check the connections at the coil and ignition switch. I don't think a dizzy alone would account for all the problems you have described.
Sorry for such a muddled guess, but I will think about it some more and if I have a better idea, I will let you know.
You've helped me on several occasions, but I am not sure I can help you very much here.
My thoughts are the sound from the radio is not "cutting out", but the radio is losing power intermittently. The tach going to zero would also indicate some type of a pulse loss since it is wired back to the coil (-) terminal. It would seem this intermittent loss of power (maybe at the coil?) might account for the truck being hard to start at times or having the engine unexpectedly die on you. If it is a loose connection, then the truck might then be able to then be started simply by touching the right area.
My best guess is to double check the connections at the coil and ignition switch. I don't think a dizzy alone would account for all the problems you have described.
Sorry for such a muddled guess, but I will think about it some more and if I have a better idea, I will let you know.
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Thanks Greg, I agree with power interrupt, sorry for not posting better.
The radio (sound) cuts off & on, recovering by itself. When the engine shuts off it's like you flip the switch. I am able to recover most times as soon as it stops rolling by open hand jiggling wires on the left side of the dash.
I have gone a couple miles, 300 ft. yesterday 20ft. It has re-occurred, occurred only once on a run. Acted up and next time out no issues.
I don't mind changing out the coil, but would like to have a good idea that is the culprit first.
thanks
John
The radio (sound) cuts off & on, recovering by itself. When the engine shuts off it's like you flip the switch. I am able to recover most times as soon as it stops rolling by open hand jiggling wires on the left side of the dash.
I have gone a couple miles, 300 ft. yesterday 20ft. It has re-occurred, occurred only once on a run. Acted up and next time out no issues.
I don't mind changing out the coil, but would like to have a good idea that is the culprit first.
thanks
John
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Postmaster
Joined: Nov 2001
Posts: 3,351
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From: Escondido, CA
I am sticking with the center post on the ignition switch personally. Either a loose nut on the post or no nut at all and the years of jiggling around has pulled the connector beck from the switch.
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Joined: Jan 2007
Posts: 11,564
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From: Tucson
John, sounds familiar to a problem i had
My 66 has a unilite dist with a box on the firewall... the wires going to the box were bad. it would just cut out, sometimes start back up and sometimes not. i changed out the junk unilite and installed a pertronix ignition, problem solved. i got rid of the box all together.
My 66 has a unilite dist with a box on the firewall... the wires going to the box were bad. it would just cut out, sometimes start back up and sometimes not. i changed out the junk unilite and installed a pertronix ignition, problem solved. i got rid of the box all together.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
This is a similar problem that effects DuraSpark ignition modules (box on left fender apron).
The three step scenario of a failing DuraSpark ignition module.
1) Module overheats, engine dies. Module cools down, engine restarts almost at once.
2) Module overheats, engine dies. Module cools down, engine restarts in an hour or so.
3) Soonor or later...usually sooner, the module overheats, burns out. Now the engine will not restart.
Since the module only fails when it overheats, taking it to an autoparts store to be tested usually doesn't work, unless the puppy has burned out.
The three step scenario of a failing DuraSpark ignition module.
1) Module overheats, engine dies. Module cools down, engine restarts almost at once.
2) Module overheats, engine dies. Module cools down, engine restarts in an hour or so.
3) Soonor or later...usually sooner, the module overheats, burns out. Now the engine will not restart.
Since the module only fails when it overheats, taking it to an autoparts store to be tested usually doesn't work, unless the puppy has burned out.
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
I am good with your suggestions. Any ideas on the radio speakers.
I am using a coil out on the front of the engine.
Other than cold start not wanting to fire a couple times, it has refired quickly after shutting down. Don't mind replacing the coil, just wanting to make sure that is where the issue is.
John
I am using a coil out on the front of the engine.
Other than cold start not wanting to fire a couple times, it has refired quickly after shutting down. Don't mind replacing the coil, just wanting to make sure that is where the issue is.
John
Thread Starter
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Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Drove the truck this morning to do a little project. Got ready to leave and the truck wouldn't start and the speakers were off & on bad. I left the ign. sw. on, slipped out, got down where I could see the fuse panel. By moving the wires 4-6" out from the block all kinds of changes were happening. The speakers got steady on, I crawled in and it fired up.
Not discounting anything offered, but it keeps coming back to the wires under the dash. I keep hoping it will heal itself.
John
Not discounting anything offered, but it keeps coming back to the wires under the dash. I keep hoping it will heal itself.
John
Elder User
Joined: Oct 2009
Posts: 825
Likes: 2
From: Dallas, Texas
Me and a few of the guys will be holding an all night prayer vigil down at the shop in hopes that the powers that be will drive out the foul demons from your wiring harness.
