1991 3g alternator not charging

[AeroCoupe]

Have you checked the voltage at the battery (meter to the positive and negative terminals)? If not do so and then move the red meter lead over to the battery post on the alternator and the black meter lead to the case. You should get the same voltage within a tenth or two. This will indicate if the case is grounded or not.

Best way is to do a voltage drop test to ensure that the alternator case is grounded and your connections are good.


View: https://www.youtube.com/watch?v=EMS8On17BnM

 

[BigShowJoe]

Have you checked the voltage at the battery (meter to the positive and negative terminals)? If not do so and then move the red meter lead over to the battery post on the alternator and the black meter lead to the case. You should get the same voltage within a tenth or two. This will indicate if the case is grounded or not.

Best way is to do a voltage drop test to ensure that the alternator case is grounded and your connections are good.


View: https://www.youtube.com/watch?v=EMS8On17BnM

Yeah I went down that road early on.

 

[Blown88GT]

...Other than that mine is wired just like that diagram.

Got everything installed and wired without using the original black/orange power wires, and I get no charge with the engine running....

That diagram above is incomplete.

If you removed these wires, it will not charge. You also need to connect the stator post on the 3G to the "S" terminal on the regulator. See wiring diagram in attached file.