Troubleshooting alternator

[Siobhan]

I’m hoping the forum can help me determine that I have made some obvious newbie mistake and not that I need to replace my old model Motorola alternator. We are testing this new to us ‘67 A4 after having replaced and rewired the whole thing. So far this is what I’ve got:

1. Wiring the ‘clip connection’ from the regulator to the pos terminal on the coil
2. Connecting the output terminal to the pos on the starter solenoid (and this right back to the pos battery bank
3. Wiring the ‘clip connection’ on the regulator to nothing and taking the output of the regulator off the alternator (is this the exc post?) and wiring it directly to the pos on the coil

None of these scenarios create any voltage increase when we turn the engine on. We are on the hard right now so running the engine with water spraying the cutlass bearing and raw water from a bucket by not for too long at a time. We are testing at high idle.

I understand that a lot has been written on this subject and I think I’ve read most, but any suggestions would be greatly appreciated.

Thanks!

Siobhan

[ndutton]

See if this picture helps. I can see at least one errant wire in your picture.

[Siobhan]

Exc

Yeah, that’s where the regulator attaches to the alternator (we have tested it with that attached) at the ‘exc’ terminal (I’m still a bit in the dark about the way it works). My understanding is that one trouble shooting step is to remove the regulator from the equation by connecting the alternator ‘exc’ terminal directly to the pos on the coil. That’s how it’s currently wired.

[ndutton]

remove the regulator from the equation by connecting the alternator ‘exc’ terminal directly to the pos on the coil

I've never done that so take this for what you paid ($0.00) but I would expect removing the regulator from the system would allow the output voltage to spike.

[Siobhan]

Rebuild necessary

Exactly. That’s the idea. And since we’ve also removed the other possible external wiring failure as the cause by wiring the output of the alternator directly to the battery positive, it must be something internal to the alternator itself, unless there’s something I’m missing here. I guess I’ll take it to a rebuild person tomorrow

[ndutton]

Replacing might cost less than rebuilding. It also might be an excellent opportunity for an upgrade.