Voltage Regulator Problem??

Discussion in 'Electrical and Ignition' started by coalman, Jun 9, 2018.

  1. coalman

    coalman Well-Known Member

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    Voltage surges up and down quite a bit, any ideas on this?? If I need a new regulator, recommend original vs electronic? Thanks a bunch....
     
  2. 67Dart273

    67Dart273 Well-Known Member

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    Try the following, make up a temporary wire. disconnect the VR IGN connection, and connect it direct to battery (or at starter relay "big stud) temporarily. See if this tames the surge.

    if not stab a meter probe onto the battery NEG post and the other into the mounting flange of the VR. You want very low, lower the better, zero volts is perfect. If not, the grounding needs improvement.

    Do that measurement with engine running fast to simulate "low to medium cruise" and first with all accessories off, and again with lights heater, whatever loads you can bring on powered on.

    If this does NOT seem to be the problem, have a look at the alternator brushes and slip rings. Worn, dirty/ greasy, gummed up, stuck, etc

    If that is not the case replace the VR
     
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    • coalman

      coalman Well-Known Member

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      Thanks...
       
    • coalman

      coalman Well-Known Member

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      Did your recommended step 1, the volt meter went to 16 volts, it did have an impact on the surge. Thanks
       
    • 67Dart273

      67Dart273 Well-Known Member

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      This may mean that you have poor grounding between battery and VR. What year? This the electronic 70/ later or mechanical 69/ earlier?

      If it's mechanical it may just be out of calibration, if you replace it you will likely get an electronic "look alike" replacement
       
    • coalman

      coalman Well-Known Member

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      I have a very good ground for the regulator to the body, the regulator is an after market electronic, that looks like the original.
      Do you recommend the mechanical over the electronic? Thanks
       
    • 67Dart273

      67Dart273 Well-Known Member

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      What did the ground voltage test I outlined earlier show?

      You need the following:

      VR ground MUST be at same voltage as battery NEG

      VR power/ sense MUST be at same voltage as battery POS

      If these two are met and the voltage still charges high (over 14) then either you have a wiring problem causing the field to be bypassed, the VR is out of calibration, or the battery is bad

      Next, if you have a known good battery out of something else, might swap in long enough to see if it changes
       
    • coalman

      coalman Well-Known Member

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      I am confused are you talking about Voltage or OHM'S?