Dual Field Alternator Conversion - New Electrical Gremlins!

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Detroit Iron

Detroit Iron

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I converted my '64 to a dual field alternator. So, needless to say, I got a dual field alternator and a new reproduction harness specifically for the dual field upgrade including ballast etc.

Now that I've done this, I have an electrical "crackling" noise coming from inside the distributor. Ordinarily I would just think there was a short in the distributor, but... this happens with the key in the OFF position! Why is there voltage to the distributor with the key off??? I replaced the ignition switch thinking it was staying on somehow. No cure.

I'm baffled as to how voltage is getting to the coil and distributor. Anyone have an idea? Thank you.
 
is there "actually" voltage present and where is it? Hard to say, might be something crossed up in the new harness, ??
 
If you unhook the ignition switch, that is remove the connector, this goes away?

Is there added / modified wiring in the car?

What do you have for a service manual / wiring diagram?
 
67Dart273 said:
If you unhook the ignition switch, that is remove the connector, this goes away?

Is there added / modified wiring in the car?

What do you have for a service manual / wiring diagram?
Click to expand...

Correct, even with the ignition switch unplugged there is voltage to the coil. I have no other modified wiring. That's why I purchased a resto dual field harness. I wanted to be sure it was all correct.
 
No. There is no other circuit that should be "feeding back" like that.


Sounds to me like there is something crossed up in that harness. If this were an older harness that could have been damaged by a high current short, I'd suspect "meltage" in the harness, IE a couple of wires melted together.

I cannot think, really what might be doing this. You might have to "rig" in order to separate the general area of the problem, something like this:

Remove all the engine bay connectors from the bulkhead connector so that it's "blank."

But now, you cannot get power into the car. You also need to protect against "screw ups" so you don't burn things up. You have an old headlight? How about a tail / stop lamp socket? What you want is a heavy wattage bulb.

"Rig a heavy bulb" such as a stop or backup lamp or headlight with alligator clip leads.

Figure out which bulkhead connector terminal is the RED fuse link That is, power feeding into the interior. Hook one end of your lamp to that, and the other end of the lamp to battery hot. This will feed "protected" power into the car interior.

Double check that items internally in the car operate. headlight switch should make the dash lamps work, and dome light should work.

With the ignition switch connector engaged, turn the key to run and to off and verify that the dark blue "run" wire goes on and off.

If that checks out, get a wiring diagram and do a wire by wire continuity check on the engine bay ignition harness wiring. Start with the dark blue "run" circuit. It should feed off to the ballast connector, and the VR. Check for continuity from that wire to all other wires in the firewall connector.
 
So I worked backward from the problem (which seemed to be at the coil). I ended up under the dash, which was strange to me since nothing was changed inside the car. Anyhow I found the dash voltage regulator to be "burnt". I think it was in a closed state which sent voltage back out to the engine. Once I removed the dash regulator, I no longer had voltage on the blue wire with the key in the off position.
 

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No, there's something else. You have some harness wires crossed or melted

The IVR receives it's power from the ignition switch----same power operates oil and brake warning lamps. The IVR output only goes to the temp and fuel gaues (unless Ralley) through the gauges, and then out the sender wires to the temp sender and to the fuel tank.

That may be very bad. You may have "other things" burned up including part of the cluster PC board and or gauges.
 
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