Blowing up Alternators..

Thread in 'Technical Questions' started by s13silvia, Jul 7, 2019.

  1. s13silvia

    s13silvia doughnut muncher

    Joined:
    Nov 25, 2004
    Posts:
    1,566
    Likes Received:
    17
    Location:
    Highlands, Scotland
    OK, this is pissing me off - for my car I CANT get an OEM spec replacement new or second hand, I've seen one in Japan for sale but they are trying to utterly rook me for postage and would cost nearly 800 for a second-hand unit in unknown condition.

    All wiring is stock, on a 40,000 mile car.
    first time revving the car past 3k the lights dimmed, then I revved it again and smoke started pouring out the bonnet and it blew a heap of fuses inside. It was the Alternator.

    I've had mine fully refurbed at a cost of 350, every component was replaced. I put in a new battery before testing.
    Turned on - no increase in Batt Voltage
    Gave it a little rev with the volt meter attached and it blew up in my face. Luckily im okay but was a bit hairy.

    Belt is not overtightened; I cant find any faults or shorts.

    I'm going to send the Alternator back, but what should I be looking for here guys, because my brain tells me it's more likely there's a background problem that the previous owner was aware of than 2 alternators being faulty.
    The only thing I can see visually is in the fuse box there's a connector (im not sure where it goes to) and the plastic insulation is a bit melted so guessing some heat went through here; I wont be able to get a replacement connector either.
     
  2. Zammish24

    Zammish24 Member

    Joined:
    Nov 19, 2016
    Posts:
    169
    Likes Received:
    7
    check the wiring mate, sounds like you're blowing the regulator causing it to overpower when revved making it pop fuses.
    I dont know what car it is but most alternators ive played with (mainly toyotas) have 3 wires and 1 battery wire.
    one to battery, ignition and lamp on the dash as a 'field' wire.
     
  3. BenRice

    BenRice Well-Known Member

    Joined:
    Apr 23, 2014
    Posts:
    1,765
    Likes Received:
    300
    Location:
    New Zealand
    For an internally regulated alternator there should not only be the main power feed (thick wire) but also another 12V wire that is thinner. This is crucial for the regulator to work

    I mistakenly didn't have this hooked up and saw 15-16 volts in my car

    I'd be making damn sure this wire is hooked up dude
     
  4. s13silvia

    s13silvia doughnut muncher

    Joined:
    Nov 25, 2004
    Posts:
    1,566
    Likes Received:
    17
    Location:
    Highlands, Scotland
    Hmm, i'll have to voltage check the smaller wires in the rear plug to make sure I'm getting the +12 bud; thanks for the advice!!
     

Share This Page