HELP ! Voltage Regulator or Alternator ????? | FerrariChat
Buy

HELP ! Voltage Regulator or Alternator ?????

Discussion in 'Technical Q&A' started by parkerfe, Apr 26, 2004.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    12,887
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    #1 parkerfe, Apr 26, 2004
    Here's the deal. When I drive my BB512i it runs great. However, once I turn it off it won't start as the battery is DEAD. I can push it off and it drives fine again. It has a new Optima red top battery. When I get back home I recharge the battery and it will start and run fine again, but after I drive it a while the same thing happens. I had a shop test the battery and alternator with one of those computer testers. At idle, my battery show 13.8 volts and 38 amps with the car's own ammeter showing a slight positive needle . However, when the radiator fans come on or the A/C is turned on, the voltage drops to 11.4 volts and the amps to 0 amps with the car's own ammeter then showing a positive 40amp needle. Accoding the the tech that did the test, that positive needle on the car's ammeter indicated that the alternators are doing their job. That technician that did the battery/alternator test said it looks to him to be a bad voltage regulator. Others have told me that it sounds more like one of my alternators is working and the other one is not? FYI, a Boxer has two alternators but only one voltage regulator. What do you guys think ?
     
  2. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,223
    TN
    #2 308GTS, Apr 26, 2004
    I am not that familiar with the Boxer setup but I assume that each alt. has its own voltage reg. on the back of them. Is this correct? If so, the best way to test it would be to run the car up to temp and check the V at the battery with no access. on then with access. on and note the difference. Then if you notice a large drop like what you already reported test each alternator individually. This will tell you which one is not charging. Since you said one was charging and the other wasn't I am assuming that they each have their own volt. reg. on the back of them otherwise neither would be charging. When I say test each alt. that means to put the probe on the back of the alt. where the + line connects. (should be a stud coming out of the alt. with a nut on it holding the wire on)
     
  3. LJH

    LJH Rookie

    Feb 2, 2004
    34
    CT
    Full Name:
    Jack Horner
    #3 LJH, Apr 26, 2004
    Franklin, my email is down, so I can't send you the thread directly, however for an explanation of all the possible resolutions to your electrical (charging) problem go the Ferrari Club of America's site, Technical section, Electrical Sub-section, and look for the Thread titled Ammeter Readings (negative), authored/asked by LJH (me). I am awaiting the fix for my car and will share it w/ you when acomplished. Meanwhile, check out that thread. Jack Horner
     
  4. Dave

    Dave F1 Rookie

    Apr 15, 2001
    2,722
    Little Rock
    Full Name:
    David Jones
    #4 Dave, Apr 26, 2004
    Frank, my 79 had similar problems...
    I took the alternators to a local alternator shop and had them rebuilt at a reasonable price. You can also have them up-rated to produce more amps.
    It's been a while but I think it was about $130.00 each.
     
  5. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    12,887
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    #5 parkerfe, Apr 28, 2004
    I am also looking to see if it's just a bad connection some where between the alternators and battery? I'll post what I find out .
     
  6. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Owner Rossa Subscribed

    May 4, 2001
    36,563
    Birmingham, AL
    Full Name:
    Tommy
    #6 Dr Tommy Cosgrove, Apr 28, 2004
    If your alternator(s) are bad PLEASE do this instead of getting new or remanufactured ones. It is no big deal and a shop can do it in just a couple of hours. Besides, you will probably just buy a rebuilt one anyway - discounted with your core - so you will be getting the same thing except you won't be paying someone to simply resell a used one with a handsome Ferrari markup. Plus you can have it back the same day instead of waiting for one on backorder.
     
  7. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    12,887
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    #7 parkerfe, Apr 28, 2004
    There is a great rebuild shop named Sleepy Hollow in Cumming very near my home that I plan to use if that turns out to be the problem.
     
  8. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    12,887
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    #8 parkerfe, Apr 28, 2004
    As it turned out the passenger side alternator was only producing 25 amps rather than the 55 amps it is designed to produce. One of the battery cables also had a stripped retaining bolt causing resulting in a bad connection. I have replaced the stripped bolt and am having the alternator rebuilt at Sleepy hollow for $100.00.
     
  9. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
    Full Name:
    Phil Hughes
    #9 ferrarifixer, Apr 29, 2004
    Also, have a good look at the engine earth cable and the main battery earth cable on the chassis rail. You may have to remove the battery or the tray underneath to see if there's any rust or electrolysis.

    The starter solenoid could also be a problem, usually from having it's cable overtightened and twisting the internal contacts out of alignment.
     

Share This Page