1g to 3g alternator problem

Discussion in 'General Maverick/Comet' started by D-Man, Jan 27, 2020.

  1. D-Man

    D-Man Member Supporting Member

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    I purchased a Tuff Stuff 7771 3g alternator for my Comet. It came with a harness and I also purchased a separate 1g to 3g harness. I have it all hooked up per the directions that came with the alternator and the thread picture here.
    http://mmb.maverick.to/threads/voltage-regulator-wiring.115911/page-3
    The only difference is the yellow wire from the plug is connected to the power terminal on the alternator instead of running back to the solenoid. I have a 4 gauge wire from the power terminal to the solenoid and I am not running a fuse. That is the way the alternator directions had it. But the new alternator does not charge the battery. I did solder in the 500 ohm resistor and my Alt light burns bright for a couple of seconds when I first turn the ignition on. The car starts and runs but the voltage goes from 12.5 before starting to 12.2 before the electric fan comes on. Revving the engine does not increase the voltage at the battery at all. Shortly after, the voltage drops and soon after that the car dies. The battery is brand new as is the alternator. I have tried both harnesses and neither will make the alternator charge the battery. Besides taking the alternator in to get it tested, is there anything else I should try?
     
  2. bmcdaniel

    bmcdaniel Senile Member

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    Sorry, I have to ask... Is the charge wire connected to the battery side of the starter solenoid?
    If so, it sounds like the alternator isn't turning on. Make sure the blk/wht wire is securely plugged in to the connector on the back of the case. Make sure you have 12 volts on the grn/red wire when the key is on. If all of that checks out you probably have a bad regulator.
    When you do get it working you should consider connecting the yellow sense wire to the solenoid or the battery + terminal (that's where I ran mine). It makes the alternator much more responsive to the battery.
     
  3. D-Man

    D-Man Member Supporting Member

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    I took the alternator to have it tested and it was not charging. Glad it was the alternator and not my wiring. Bought it from Summit and called customer service and another one is on the way. They provide a return label with your shipment so it’s easy to send back. :whew:
     
    bmcdaniel and 71gold like this.

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