78magnum electrical problem

[78MAGNUMJOHN]

I have a 78 magnum that I put way to much money into but it's a great car.problem I'm having is when driving on freeway the motor shut's off and comes back on.only when driving is when it happens.under torque conditions.sometimes I turn the key nothing happens,turn it again then it starts up but the clock resets at 10:00 like I had no power coming in.any help would be great.thanks.

 

[rlem1977]

Seems like you're losing a battery connection, either positive or negative. Probably why clock resets.

 

[78MAGNUMJOHN]

thanks that is one of the things we will be looking at this week. I had it at my mechanics one day and he started it and it shorted out on the positive side of the battery.

 

[tommytmopar]

I had a Dakota with that failure. I would be driving and suddenly dead. All gauges fell and I was on side of road. I would go out and move wiring harness till dash lights came on. Then back in business. I had a broken connector at the computer.
I would think you have an open circuit rather than short. Do you have Ecu on 78? If so that’s possible. I experienced that condition with my Roadrunner. Would die then start right back up. Finally it died for good after causing problems for months.
If you can duplicate the failure move your harness to search for an open circuit. Good luck troubleshooting.

 

[YY1]

My 93 Dakota had the same issue.
Was a bad solder joint on the ECM board.
I had to get out and flex the board to get it going again.

Have you checked the grounding mounts of your brain?
...or the brain it's self?

 

[78MAGNUMJOHN]

I had a Dakota with that failure. I would be driving and suddenly dead. All gauges fell and I was on side of road. I would go out and move wiring harness till dash lights came on. Then back in business. I had a broken connector at the computer.
I would think you have an open circuit rather than short. Do you have Ecu on 78? If so that’s possible. I experienced that condition with my Roadrunner. Would die then start right back up. Finally it died for good after causing problems for months.
If you can duplicate the failure move your harness to search for an open circuit. Good luck troubleshooting.

 

[78MAGNUMJOHN]

I do have ecm on it.very hard to duplicate. my mechanics would spray water mist around to see if something would spark.I'm thinking and hoping it's the battery connector.thanks.

 

[rumblefish360]

Check the fuesable link as well as the bulkhead connections.

Wait, your running a Lean burn? They are very well known to just cut out when running.
If so, disconnect it and run the old conversion back to the older set up. It used to be the Orange box, vacuum advance distributor, ballast resistor and harness. I would just substitute a Chrome box for the orange.

 

[78MAGNUMJOHN]

Check the fuesable link as well as the bulkhead connections.

Wait, your running a Lean burn? They are very well known to just cut out when running.
If so, disconnect it and run the old conversion back to the older set up. It used to be the Orange box, vacuum advance distributor, ballast resistor and harness. I would just substitute a Chrome box for the orange.

 

[78MAGNUMJOHN]

it doesn't cut out when in park when running motor,only when i'm driving,it will stop running and run again like flipping a light switch.almost feels like a strong head wind hit the car.maybe a new ecm box?

 

[rumblefish360]

Again, double check wiring. Delete, remove, disconnect the LeanBurn ignition system, install the older set up, ‘73 ignition system.

it doesn't cut out when in park when running motor,only when i'm driving,it will stop running and run again like flipping a light switch.almost feels like a strong head wind hit the car.maybe a new ecm box?

Click reply, wait a few seconds, mouse to where you want to start your reply, above or below the quoted message, click, type away.....

 

[dodge1972]

Clock resetting would indicate a complete power lose to the cabin. Recommend checking steering column wiring and switch. Red wire at the base connector has a history of overheating. If discolored, install a new short section around the connector. Following the same red wire though your firewall to the battery. Check the or replace your red battery cable and fuse link. Also confirm the remainder of the red wire is in good condition. While running check the voltage level of the battery and the potential of the red wire within on both sides of the firewall. Also keep in mind your battery maybe defective internal damage due to a shorted condition. I would replace it Good Luck.

 

[78MAGNUMJOHN]

Clock resetting would indicate a complete power lose to the cabin. Recommend checking steering column wiring and switch. Red wire at the base connector has a history of overheating. If discolored, install a new short section around the connector. Following the same red wire though your firewall to the battery. Check the or replace your red battery cable and fuse link. Also confirm the remainder of the red wire is in good condition. While running check the voltage level of the battery and the potential of the red wire within on both sides of the firewall. Also keep in mind your battery maybe defective internal damage due to a shorted condition. I would replace it Good Luck.

 

[78MAGNUMJOHN]

would that be #31 red wire on bulkhead connector? have discussed that with my mechanic.so your saying put new splice in and go around the bulkhead.that is something we're probably going to start with and replace fusible link.thank you. I also have problem with wipers.they go back and forth normal then they go wide back and forth and won't go into park position when I turn them off.I'm thinking gears are worn out. thanks again john.

 

[dodge1972]

John, Passpassing the bulkhead connector is a common practice when there is corrosion on the pins. Avoid using butt splices for this application, soldering is old school, but still provides the best solution. Install red shrink tubing using a heat gun over your splices. tape will fall off over time and allow moisture to setin. Microswitch within the wiper motor should return it to a home position. Operates the same as hideaway lights. If you can find a spare used unit try it first prior to dismantling the wiper system.

 

[78MAGNUMJOHN]

John, Passpassing the bulkhead connector is a common practice when there is corrosion on the pins. Avoid using butt splices for this application, soldering is old school, but still provides the best solution. Install red shrink tubing using a heat gun over your splices. tape will fall off over time and allow moisture to setin. Microswitch within the wiper motor should return it to a home position. Operates the same as hideaway lights. If you can find a spare used unit try it first prior to dismantling the wiper system.

 

[78MAGNUMJOHN]

thanks again for the info.dropping car of tomorrow at mechanics.will let you know out come.john.

 

[dodge1972]

John, Also check the battery black cable for good clean ground to include the pig tail to the chassis. Its typically not an issue, but its just good maintenance. One final point, the engine will shut-down if you loose battery voltage to alternator. In your case, I believe your loosing the battery voltage to the ignition switch good luck

 

[78MAGNUMJOHN]

John, Also check the battery black cable for good clean ground to include the pig tail to the chassis. Its typically not an issue, but its just good maintenance. One final point, the engine will shut-down if you loose battery voltage to alternator. In your case, I believe your loosing the battery voltage to the ignition switch good luck

 

[78MAGNUMJOHN]

bypassed the bulkhead connector and went for a ride put in steely dan aja 8- track (yes 8-track player) went on the freeway for 30 miles came back and there was no interruption of the motor of any sort.thanks for all the input.will try to post pics of my car when I can get my friends kid to show me how (lol).