Hemi Alternator Wiring

New Hemi Engine Swaps

  1. 408 swinger

    408 swinger FABO Gold Member FABO Gold Member

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    Does anyone know if there's a difference in the internal wiring/function between the 03-08(early) and the 09- newer(Eagle) alternators? Had to switch engines in my son's Scamp. Replaced the 04 with a 2012 5.7. Has the car front accessory drive. I wired the "early" alternator like the old square backs. Two wires out of the back, then into the voltage regulator. Yes, I know. Higher output will burn the car down. Well, when we put the newer engine in, we had to use an appropriate alternator for the year. The spacing is different between the two. So, when we wired in the new pigtail for the alternator, and plugged it in, it Waaaaaay over charges. So much so, that it pulls the engine down. Rev it up, belt squeels like a pig! So, that's my issue. Any thoughts FABO? I should also mention, tried new regulator, grounded properly. Thanks, all!
     
    Last edited: Jun 29, 2020
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    So far as I know they are all wired just like the 70/ later isolated field setup. CHECK BOTH BRUSHES and make sure they are both infinity to ground (open to the case), and continuity between each other
     
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    • Edsrt

      Edsrt Well-Known Member

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      I am pretty sure that the two wires are not the same as the old alternator . One is a field wire and one is a sensing circuit for ecm control. My megasquirt instruction call for 1969 mechanical voltage regulator
       
    • 67Dart273

      67Dart273 FABO Gold Member FABO Gold Member

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      • 408 swinger

        408 swinger FABO Gold Member FABO Gold Member

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        I checked as you said. That checks "good".
         
      • 408 swinger

        408 swinger FABO Gold Member FABO Gold Member

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        I was wondering this. If that's the case, would one of the wires(sensing wire) be open? I checked both wires as Del suggested and it checked out that way.
         
      • 408 swinger

        408 swinger FABO Gold Member FABO Gold Member

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        That one wire deal would be the way to go, had I not already invested (and installed) in a 200 dollar remand.:BangHead:
        Too bad there's not a backyard method to convert what I have to one wire.
         
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