alternator issues

Lincoln LS

  1. romois9

    romois9 LVC Member

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    On my 04 3.9 alternator only puts out 12.56 volts. So I got a new alternator, same issue. Even swapped batteries. I can run and start it no problem as longs as I don't run headlights. I was hoping the new alternator would fix the problem but it has the same exact problem still. Any ideas? Already checked the alternator sense fuse.
     
  2. LS4me

    LS4me Dedicated LVC Member

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    Motorcraft or aftermarket alternator? The LSes electronics don't play well with most non-OEM electronic parts. There is a whole discussion on this.....
     
  3. romois9

    romois9 LVC Member

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    oem alt

    Well the alternator I took off was doing the exact same thing, it was OEM
     
  4. joegr

    joegr Dedicated LVC Member

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    Your answer is unclear. Yes, the original was OEM. Is the replacement OEM?
    It's easy to see a new non-oem alternator have the same symptoms as an old failed OEM alternator. The non-OEM alternators don't use the correct voltage regulator/controller.
     
  5. romois9

    romois9 LVC Member

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    It's a motorcraft, one issue was a ground it boost the volts up to 13 but doesn't drain with the lights on. My car has never produced more than 13.4 volts even when I first got it.
     
  6. 1LoudLS

    1LoudLS Dedicated LVC Member

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    what are you using to test the voltage, and exactly how are you checking it?
     
  7. romois9

    romois9 LVC Member

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    Volt meter at the battery
     
  8. joegr

    joegr Dedicated LVC Member

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    What voltage does it read on the battery an hour after the car is turned off?
     
  9. romois9

    romois9 LVC Member

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    11.8
     
  10. joegr

    joegr Dedicated LVC Member

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    Are you sure that your meter is reading accurately? Do you have access to another meter to verify it by?
     
  11. romois9

    romois9 LVC Member

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    Even with another meter it shows the same. I didn't put a new battery in it so that could be an issue. Does anyone else have an alternator ground issue with theirs
     
  12. LS4me

    LS4me Dedicated LVC Member

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    A dead/failing battery can kill an alternator and vice versa........
     
  13. romois9

    romois9 LVC Member

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    Well my alternator isnt getting a good ground. Does that make any sense?
     
  14. LS4me

    LS4me Dedicated LVC Member

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    How do you know?
     
  15. romois9

    romois9 LVC Member

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    When I add a ground to the alt case. It seems to produce more volts.
     
  16. LS4me

    LS4me Dedicated LVC Member

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    Sounds like a bad alternator to me. Who rebuilt it??
     
  17. romois9

    romois9 LVC Member

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    Are they internal regulated or external
     
  18. romois9

    romois9 LVC Member

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    And it doesn't drain the battery unless I turn the headlights on
     
  19. LS4me

    LS4me Dedicated LVC Member

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    I believe the PCM controls the output. Honestly, there's more information in the H.O. alternator thread on how the alternator works and it's relationship with the PCM between the generations.
     
  20. romois9

    romois9 LVC Member

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    And it doesn't drain the battery unless I turn the headlights on
     
  21. Telco

    Telco Dedicated LVC Member

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    That's 1st gen, 2nd gen doesn't have that problem.

    Replace the battery and alternator together, should be good after that. If you suspect a grounding problem, when you replace them clean and sand all ground connection points until you see shiny metal on both the wire and the metal it's bolted to. Run the wiring with your hand too, to make sure there isn't any damage to it.
     
  22. 1LoudLS

    1LoudLS Dedicated LVC Member

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    well the alternator bolts to the engine, so that is a pretty good ground (unless the alternator is not tight and flopping around) you can check the engine ground (or just add another one)


    also since it wasnt a new battery that you tried, where did you get it from? what's its age? how was it being stored? maybe that battery is crap too...
     
  23. romois9

    romois9 LVC Member

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    I had it laying around for a couple of months, when I took it from work and tested it showed 12.4 volts and 850+ cca optima. It was made 4/12 just like the 66 series I swapped it with.
     
  24. romois9

    romois9 LVC Member

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    Clarification I swapped my 66 with the optima
     
  25. jrdnhsnbrg

    jrdnhsnbrg Active LVC Member

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    Your battery is toast. Replace it first. Your alternator might be fine but can't keep up with the load the bad battery is putting on it and the headlights, but can keep up with just the battery.
     

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