Charging issue

-
340luckyman

340luckyman

FABO Gold Member
FABO Gold Member
Joined
Apr 23, 2014
Messages
52
Reaction score
21
Location
Maryland
I have 70 dart that i rewired using a R Francis kit. I also relocated the battery to the trunk. Everything works fine but I can't get the alternator to charge the battery. I took the alternator out and had it tested and it was okay. I reinstalled the alternator, pulled a field wire and connected it to ground, started the car and and the volt gauge finally showed a charge over 12.4. (Thanks to 67dart273 for the test from another post). I have tried (3) different vr's, grounded the vr's with a jumper wire as well as the standard ground and still can net get more than 12.4 volts. Any suggestions are appreciated!
 
What are you using for a VR, AKA, early 69/ earlier Mopar, 70 / later Mopar, or the Ron Francis? Likely a simple mistake in wiring. NONE of the wiring kits are very clear as to Mopars in my opinion.

Also, detail "how you think" you have it hooked up
 
It's a 70 and later type that was on the car prior to rewiring. I switch it out to A mopar 3438150 and then to a new Napa Echlin vr38. I have one alternator field wire going to the vr field and the other alternator field wire spliced with a wire labeled Reg Alt feed to the other vr connection.
 
From the factory, the blue wire that plugs into the voltage regulator has 12V switched +. From there the blue and green went directly to the alternator as field wires.
 
I'm assuming the Reg Alt feed is the same as the 12v switched factory blue wire. I have this wire and the alt field wire in one side of a crimp connector and one wire coming out the other end to the vr.
 
I don't know, not having Francis diagram. I bet this is the problem

Here is a simplified diagram, if you don't have........

Dual_Field_Alternator_Wiring.jpg


Here is essentially what you have. The VR MUST be grounded, but you seem to have addressed that

Switched 12V ignition goes to either field, and to the VR blue IGN connection.

Then, the F wire goes only one place......directly from the VR F terminal to the remaining field terminal on the alternator. The VR controls "the amount of ground" in a manner of speaking on this field connection

Also, don't discount silly mistakes, like, AKA, a defective VR connector, broken terminal in the molded rubber, etc. or a loose one not making contact on the VR terminals.
 
I no longer have a ballast resistor so the ignition wire goes straight to the vr with the alt wire. I guess the next step is to start checking what i have done and maybe try another new vr plug. Does it matter where the wires land on the vr?or are they specific ignition/field? If you would like a copy of the R Francis diagram let me know and I can send it to you.
 
Specific? Absolutely. Go by the diagram. "The shape" of the triangular connector identifies the two.

The "top" one MUST be switched ignition and the "far right" terminal goes directly to the one field.

Sounds to me like you are down to simple wire tracing and continuity.

Make sure you have switched ignition at one field terminal and the VR "I" terminal

Make sure the VR F terminal actually goes to the remaining alternator field terminal

One way to do this is follows:

You have?? made sure you are getting switched 12V to one alternator field, right?

OK so pull off the VR connector. Check voltage at BOTH VR harness connector terminals with key "in run." They BOTH should show battery voltage.

Unhook either alternator field. The "F" terminal should go dead

=========================

Now make sure they can carry current

A.......With alternator field hooked up "normal", carefully ID the "F" terminal in the connector. Ground this with engine running. This should result in heavy charging, with engine RPM brought up a bit.

B......You can check the "I" wire the same way. Disconnect the alternator field ignition wire. Ground that terminal with a clip lead. Now devise a way (two machine screws) to insert into the VR connector and jumper the two terminals together. This should feed 12V through the VR connector down to the alternator field. Again bring up RPM. This should cause heavy charge.
 
If I have the wires crossed on the vr would that cause it to fail? Not saying I do just wanted to know just in-case I need to get another vr
 
....................I ain't sure. Might. Should be easy to figure out "if." Make sure the correct one is IGN and the correct one is field. If they were switched, and the tests above prove OK, then replace the VR "one last time." Not to belittle, but do make positively certain the VR is grounded at the case.

Frankly, I would have thought reversing them would have resulted in a short on the IGN line
 
Well I had the wires crossed at the vr and it must have fried it. I purchased a new one along with new plug, rewired them and it seems fine. The volt gauge is showing right around 13.5v at idle and just over 14v revving the engine. I didn't check voltage at the battery yet but will. Will there be a voltage drop with battery in trunk?
 
"Maybe." You will know when you check LOL. Glad to hear you are getting there.
 
You must log in or register to reply here.
-

Back
Top