Car won't shut off

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Mopar to ya

Mopar to ya

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I have a 73 Dart Sport 408 with MSD 6AL-2 programmable ignition. As in every year I drive this car to Mopars in the Park, something breaks. This year I got home, turned off the key, and the engine kept running. I had to pull the ignition fuse to shut off the car. I couldn't look into it right away, and after a week I wanted to drive the car. I put the fuse in and it started and ran well. I was driving home and I noticed I was running at 10 volts. I had 30 miles to go, but it was hot and the fans were running and I died three miles from home. When I finally got around to looking at the problems, the starter died. I finally replaced the starter today but haven't looked into the other issues. I don't know if they are related or are two separate issues. I did check voltage at the B+ terminal of the alternator and I had 12.5 volts. When I started the car I had 11.2 volts. Weird. If I leave the ignition fuse in place the battery drains. When I put it back in there is a spark at the fuse. I disconnected the positive battery terminal and when I set it aside it touched metal and sparked. How that would happen I don't understand. Anyone have any ideas? I suspected an ignition switch issue and installed a new one with no luck. I'm hoping some smart person on FABO can point me in the right direction or give me some testing advice.

 
Since we have no idea how it's wired, I have no clue. Do you use a relay to power the ignition/ charging circuits? What do you have for an alternator setup? If for example this is a three wire GM and you have it wired with no diode, resistor or lamp in the no1 exitation terminal, those can fail the internal diode trio and cause a feedback circuit much like that.
 
It uses a standard Mopar alternator, the same one used by every Mopar in the day. The only major wiring change is to the MSD ignition box, which removes the ballast resistor and also the ignition module. I have a custom dash with Auto Meter gauges with electric senders. That removed the old cluster with it's power connector issues as well. It still has most factory wiring beyond that. The vehicle also still uses the factory voltage regulator.
 
OK you mentioned "removed ignition fuse" but the factory setup HAD NO ignition fuse. What/ where is this?

Otherwise this does sound like might be an ignition switch. I have heard stories of fans causing feedback, but that should be only when they are running I would think

Start it and while it's running, try separating the ignition switch connector up there at the column
 
I should have said fuseable link. My old link was bad and I replaced it with a maxi fuse. I'm going to ground the field and see if the alternator will charge like hell. Then I'll have an idea if it's one or two problems.
 
Was there a resolution to this? Just got out of my car today and it wouldn't shut down. The ignition switch still turned the gauges /radio/accessories on and off but not the car.
 
67Dart273 said:
Since we have no idea how it's wired, I have no clue. Do you use a relay to power the ignition/ charging circuits? What do you have for an alternator setup? If for example this is a three wire GM and you have it wired with no diode, resistor or lamp in the no1 exitation terminal, those can fail the internal diode trio and cause a feedback circuit much like that.
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Thought I would bring this thread back to life, since I have the same issue in my Scamp. I use a starter relay and a three wire alternator. My question to this post, is how do I confirm that there's a diode, resistor, or lamp as described? I'm fairly ignorant to electrical components.
 
Righty Tighty said:
Thought I would bring this thread back to life, since I have the same issue in my Scamp. I use a starter relay and a three wire alternator. My question to this post, is how do I confirm that there's a diode, resistor, or lamp as described? I'm fairly ignorant to electrical components.
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You really should start a new thread. What specific alternator are you using? Model, make, like GM 12SI, or Toyota etc. Very first thing to do is find that out

Next what do you mean "confirm there's a .............." Who installed the alternator? No stock Mopar that is in the context which we deal with, has any of this. They are not used factory
 
A multi-meter might help. Use to find what is powering coil +. You may have to disconnect wires on ignition circuit, to find root cause.
 
^Hi Dave. Hope you folks are having a good weekend. Cooled down "a little" here, only mid 90's instead of mid-100's LOL
 
67Dart273 said:
You really should start a new thread. What specific alternator are you using? Model, make, like GM 12SI, or Toyota etc. Very first thing to do is find that out

Next what do you mean "confirm there's a .............." Who installed the alternator? No stock Mopar that is in the context which we deal with, has any of this. They are not used factory
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Thanks, I'll start a new thread. I'm always apprehensive to do so, because I see folks commenting all the time with "there are a ton of threads about this," or "here we go again" type stuff.

It's getting late in the day for me, so it'll be a couple days before I can get the new thread started, beginning with the answers to the questions you've asked.

...and...mid-100s in Idaho?? I thought the mid-110s in the dry heat were bad! Thankfully, the rainy season has begun.
 
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