328 Battery Light | FerrariChat

328 Battery Light

Discussion in 'Technical Q&A' started by rob lay, Mar 30, 2008.

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  1. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner Social Subscribed

    Dec 1, 2000
    64,249
    Southlake, TX
    Full Name:
    Rob Lay
    The battery light usually comes on when turning the car on and doesn't go off until it warms to 3k or so. It then never comes back on again until next restart. I believe that is normal operation.

    Saturday for first time ever the light went off normally, but running idle at ATM and then stop lights it would come back on. Later that night coming home the battery light stayed on the entire time.

    Without looking at manual I believe this battery light would be low voltage and/or negative charge?

    I haven't tested the voltage of the battery, but because of the RPM behavior I suspect the alternator?

    I guess at least once in past I did have the battery light coming on and knew I was losing electrical when the lights started diming then went dark before car dying. No electrical symptoms yet except for the indicator light.

    Thanks.
     
  2. Darolls

    Darolls F1 Veteran
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    Jul 2, 2003
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    Sparky
    Low/bad battery wouldn't cause it. Belt slipping or internal regulator/alternator heading south.
     
  3. marco246

    marco246 Formula Junior

    Mar 25, 2004
    288
    Hawaii
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    Mark
    The symptoms you describe sound like classic alternator failure. Went through this a year or so ago myself with my 328. Your battery may also be weak and need replacing. In any case, your trusted mechanic can diagnose this problem pretty quickly. Good luck!
     
  4. jon69

    jon69 Rookie

    Jan 25, 2008
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    UK
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    john
  5. Hans

    Hans F1 Veteran

    Feb 17, 2006
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    Hilversum, Netherlands
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    Hans Teijgeler
    Rob,

    I've had the same thing with the Nippondenso alternator on my plane (Subaru engine). I need to rev up the engine to 3000 rpm before the alternator starts charging my battery. I've been told that it is one or more of the diodes in the regulator going bad.

    Take out your alternator and have it looked at at an alternator shop.

    Hans
     
  6. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
    4,286
    Black Forest Germany
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    Martin N.
    Rob; I had the same on my Bosch alternator on my 308 GTB some time ago.
    The problem did develop slowly. At last I removed the alternator and the reason for this behaviour was a dirty voltage regulator. Dust and grime caused the carbons to stick. Only sometimes and depending on temperature. Rarely a problem when the car parked in my in-house garage, but worse when it parked outside.
    At last I parked my car 900 kms distant from home on the parking lot of a hotel during a fairly chilly night and when I restarted next morning it took VERY long for the battery light to go off. This initiated the final alternator replacement.
    I know several 3x8 owners with this problem and I suspect the location of the alternator causing these problems. Compared to other vehicles it collects a lot of dust and grime. Any - even long past - oil leaks make things worse.
    I found an incredible amoung of oily grime inside my alternator, caused by a lower camshaft drive oil leak fixed long ago before the alternator began making problems.
    I purchased a new Bosch alternator, because for the carbed 308s a voltage regulator is almost as expensive as the whole unit.
    For later cars like the QVs or 328s it's a different story. A thorough cleaning, a new voltage regulator and a set of new bearings seem the way to go here.

    Best Regards from Germany

    Martin
     
  7. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner Social Subscribed

    Dec 1, 2000
    64,249
    Southlake, TX
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    Rob Lay
    Thanks for the input everyone! Due for a Norwoods trip anyway.
     

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