Alternator/Control Unit or Regulator??

[GY3 71 Demon]

I was just working on my 71 340 and it wouldn't start. While checking out some things I believe I might have switched the coil wires from + to -.

I ended up figuring out it had a fuel problem but now the car is not charging (and it was okay before). Could I have burned something up like the control unit, regulator or alternator?

If so, is there one of you that might know where would be the first place to start looking?

Thanks.

 

[67Dart273]

If all you did was switch the wires AT the coil (not the battery) it should not have hurt the regulator.

Make a couple of simple checks

1--Turn key on, engine off, and hook your meter from the blue alternator field connector to ground. It should read "same as battery."

2---If this is good, remove the green field wire at the alternator, hook a clip lead from that field terminal and start the car, gently bring up RPM while watching the ammeter. It should charge more as RPM goes up. Don't get carried away

if that is good,

3--Next hook the green wire back up, and devise a way (machine screws) to jumper across the two terminals of the regulator connector after removing it.

Now remove the BLUE field wire and ground that field terminal at the alternator.

Once again, the system should charge if RPM is brought up.

4--If all the above checks out, you have shown that the regulator/ field wiring is pretty much OK, and the alternator is at least showing some output. Now remove and inspect the regulator mount, clean the firewall and regulator flange, and re-install using star washers. Pull the connector and work it in/ out several times to scrub the terminals, and inspect both the connector and regulator terminals for corrosion. Hook everything up "normal" and try once more. If you don't see a charge, replace the regulator.

 

[GY3 71 Demon]

Thank you very much for taking the time to write out the step-by-step instructions.

So you know, I did search the forum but couldn't find anything that described my dumb mistake.

Anyway, it turns out it was the regulator. I just replaced it and the car's charging like it should.

Thank you again for your help.

 

[71DodgeDemon340]

also a thing to check for to is make sure the voltage regulator is grounded properly. i had that prob and drove me crazy.

good luck

 

[GY3 71 Demon]

Just a little update in case someone else runs into this same problem...

Well, my car was charging fine after I installed the new voltage regulator. But, not being one to leave well enough alone, and after reading the suggestions to check the VR's ground, I decided to remove the newly installed VR and put back on the old Mopar VR - one last time. But before I put it back on, I used my rotary tool and removed the paint from around the front/back holes on the old Mopar VR. I then took the tool and removed the paint from the firewall around the mounting holes. I found some old star-type washers and re-installed the Mopar VR.

Wouldn't you know it - it worked! The car was charging as it should. It appears, the problem was the painted Mopar VR and the painted firewall didn't allow for a good ground. I now have an "almost new" aftermarket VR that will go into my "parts" box. It's my own fault, I actually noticed the VR wasn't securely fastened a few days ago - but, I didn't have any idea the mounting is what grounded the VR! It was just a coincidence that the problem popped up after the coil wire mix-up. ops:

All ends well - as the original VR has the Mopar information stenciled on it and looks great in the engine compartment. Much better than the aftermarket one for sure!

Thanks again FABO members! :blob:

 

[67Dart273]

I used my rotary tool and removed the paint from around the front/back holes on the old Mopar VR. I then took the tool and removed the paint from the firewall around the mounting holes. I found some old star-type washers and re-installed the Mopar VR.

Wouldn't you know it - it worked! T

.....4--..............If all the above checks out, Now remove and inspect the regulator mount, clean the firewall and regulator flange, and re-install using star washers. Pull the connector and work it in/ out several times to scrub the terminals, and inspect both the connector and regulator terminals for corrosion. Hook everything up "normal" and try once more. If you don't see a charge, replace the regulator.

So you didn't read step 4 before you bought a new regulator? Well, LOL, now you have a spare

 

[GY3 71 Demon]

So you didn't read step 4 before you bought a new regulator? Well, LOL, now you have a spare

I actually bought a regulator right after it happened and before anyone replied to my original post.

I had the alternator checked out and the VR was the only part left...at 15 bucks, I don't really mind having a spare. :coffee2: