70 Roadrunner Not Charging

[Gospel Runner]

I have the 6al MSD electronic ignition setup. I tried grounding the one field wire while the other is set to the green wire from the regulator and still no charge. I am placing a picture of the alternator, and regulator. Any help would be greatly appreciated!

 

[dvw]

The 2 terminal alternator system is simple. One wire is fed from ignition 12 volt. The second goes back to the transistorized (triangle connector) regulator (outer terminal). The other regulator terminal (center) is fed by the same ignition 12 volt feed. Doesn't matter which wire goes on which terminal at the alternator. The regulator must be grounded at the body.
Doug

 

[beanhead]

Did the problem just start on it's own or did it start after you changed something? If there were two wires connected to the alternator before, one goes on the post terminal and the other goes on either of the two flat spade terminals. (Connectors still on the wires? They will be self-explanatory as to where they go) The other spade terminal needs to ground to the alternator case.. what most guys do is take the screw out, then fold the terminal under itself and put the screw back in so that the terminal is contacting the case itself...(You may have to drill that little hole in the end of it, a little bigger so the screw can fit through)

 

[oldbee]

Make sure your 2nd “field” terminal is grounded to alt body like “bean” says.

 

[Gospel Runner]

I did change the wiring harness. It was all working fine before I changed that beehive of a mess. I had wires going to both spade field connectors. The new wiring harness only has one green wire coming from the regulator. I will try to ground one of the fields to the case and let you know how that turns out.

 

[dvw]

Do not ground a brush or field connection with the regulator shown. It will smoke the harness. Only ground the 2nd brush if using the old style single wire field harness.
Doug

 

[Gospel Runner]

I tried grounding the field terminal to the case, but it is still not charging. Any other ideas about what the problem could be? If what dvm said is true, I am glad I did not leave it running very long.

 

[Lionized]

Have you checked to ensure the terminals on your ammeter gauge are tight? This has been known to be an issue.

 

[dvw]

Have you done the suggested checks of the wiring for continuity and voltage? This regulator requires 2 wires to the alternator, along with the red output wire. Does the red output wire have 12volts with the key off? Both the blue wires at the regulator and the alternator terminal should have 12volts with the key on. The green wire at the regulator should have continuity to the green wire that plugs in at the alternator. It should not have any voltage or continuity to ground when the regulator and terminals at the alternator are disconnected. The regulator must be grounded. If this all checks ground the green wire at the regulator. Does it charge? Yes, then the regulator is faulty. No, then the alternator is faulty.
Doug

 

[Gospel Runner]

Doug thank you for this detailed check list. While I had it out, I took the alternator to Advanced Auto to have it checked and it is working properly. I will do these other checks today and let you know what I find. Again thanks for taking the time to walk me through this process!

 

[Gospel Runner]

Doug I need some clarification on a couple of things. The red output wire from the alternator; is that going to the starter? The blue wire from the regulator, I have that attached to the MSD system. The blue wire at the MSD and the regulator both had 12 volts with the key on. The green wire at the regulator had continuity with the green wire at the alternator. You stated that, "It should not have any voltage continuity to ground when the regulator and terminals at the alternator are disconnected." What are you referring to? Then you said if it is charging the regulator is faulty. If it is charging shouldn't everything be alright? It is still not charging with the extra field location grounded to the alternator case. The alternator checked out good. Could the regulator be bad? I am clearly not good with this electrical stuff, but with your help, I think I can get to the bottom if this problem. Thank you!

 

[rick tav]

gentlemen i am kind of new to the forum . I have a 70 Roadrunner 440 Plum Purple . i am having a very similar problem with the car not charging. i changed battery alternator and regulator. i have all MSD wires coil distributor and a 6A . I noticed when i step on the brake peddle the dome light noticibly dims. when i check with a meter it telss me ther system isnt charging. i keep the battery on a trickle charge but still have had times where the car wont start if i take it out and shut it off. any ideas would be greatly appreciated