328 Rebuilt Alternator Intermittent Voltage Drop | FerrariChat

328 Rebuilt Alternator Intermittent Voltage Drop

Discussion in 'Technical Q&A' started by 87rari, May 5, 2007.

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  1. 87rari

    87rari Rookie

    Apr 29, 2007
    3
    Maryland, USA
    Had my 328's alternator fail about 3 weeks ago. Towed the car to Ferrari of Washington and had the alternator rebuilt, charging system checked out, and a new battery (Interstate) put in. Bought a voltmeter that plugs into the cigarette lighter for future information/warning.

    Took the car out today. Blipped accelerator on startup as usual. Alternator light went out and voltmeter displayed 14.4 volts. Drove the car approx. 1 mile from home. Voltmeter suddenly dropped to 11.9 volts and alternator light came on. Engine RMP was approx. 3000. I turned the car around and headed back home. One block from home, voltage jumped up to 14.0 and alternator light went out. Turned the car back around and continued my trip (for the purpose of giving the battery a proper charge).

    10 miles into my trip (voltmeter reading 14.7 volts), voltage dropped to 12.1 and alternator light came back on. Turned the car around and headed home on the freeway. Voltage continued to drop. About 1 mile from home (on surface streets at approx 2500 RPM), voltage jumped from 11.9 to 13.8 and alternator light went out. Took the car home and parked it.

    Has anyone experienced anything like this? I searched the boards and couldn't find anything similar. Do you think Ferrari of Washington installed a bad alternator or could this be another eletrical issue? I'm a bit mad at them and reluctant to take the car back to them.... Thanks in advance for any help,

    Mike
     
  2. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
    Full Name:
    Paul
    Alternators are funny animals. Its like a ball of yarn a cat wound up and somehow its supposed to make eletrical energy. Some of it is pretty straight forward, like testing the stator or the field windings. But the regulator/brush part is a sealed electronic unit. Somwhere there is some regulator factory and they make that tiny part and pour hot goo in to seal it up and sell them to rebuilders. From what I have been told there is even top shelf and bottom shelf parts directly from Bosch. So it fully depends on who does thier rebuilds, as to how good of parts they use. Cheap China bearings, cheap regulators, you get a not so hot part. Same with starters and junk solenoids and drives.

    If I moved to some other part of the country tomorrow, I would call around to shops and see who they have do thier motors and alternators. Someone is known for good stuff. Take your part directly to them and you will probably have less trouble. Or just ask your dealer to fix it. Ask them who is doing the rebuilding and if they are known to be good.
     
  3. miketuason

    miketuason F1 World Champ
    Owner Silver Subscribed

    Feb 24, 2006
    15,823
    Cerritos, CA.
    Full Name:
    Mike
    There is something about that spot 1 mile from your home, if you could go around it I bet you wouldn't have this problem. That 1 mile spot from your home is call mystery spot or voltage drop spot.
     
  4. PAP 348

    PAP 348 Ten Time F1 World Champ
    Lifetime Rossa Owner

    Dec 10, 2005
    100,224
    Mount Isa, Australia
    Full Name:
    Pap
    Did you replace your battery after your failed alternator was replaced?, it has probably dropped a cell or two ;)
     
  5. ham308

    ham308 Formula Junior

    Nov 3, 2003
    358
    NE Switzerland
    Full Name:
    Richard Ham
    Classic reply Mike !!! (Also Artvonne's with his cat and a ball of string...) don't you just love Fchat.


    Seriously though, sounds like Ferarri of Washington ballsed up, (if that's a verb) and you have the proof with the voltage meter readings Mike. Have they fitted a duff regulator?
     
  6. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    18,095
    Savannah
    your voltage regulator has a failed diode assembly that is heating up and causing the problem. i would ask them nicely what, exactly they " rebuilt " as i know many shops will only replace the minimum parts an not replace everything that should be replaced. there are many parts inside an alt that are supposed to be replaced in a rebuild, and bench testing away from the heat of the engine will not always show a fault.

    you guys should mess with an aircraft Integrated Drive Generator (IDG) some time! oh, and ours are bigger than a microwave!

    :)
     
  7. DGS

    DGS Seven Time F1 World Champ
    Rossa Subscribed

    May 27, 2003
    72,603
    MidTN
    Full Name:
    DGS
    Intermittent electrical problems can drive you bald from tearing your hair out. From the alt light coming on, it sounds like the whole charging system is shutting down, leaving you running off the battery until it comes back.

    Charging systems can be a pain to diagnose, and the alt lamp only tells you that current is running through it -- not in which direction it's flowing.
     
  8. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,619
    The Brickyard
    Full Name:
    The Bad Guy
    Now I'm not familiar with 328's but, 348's have a certain quirk in the early cars. They have these STUPID bullet connectors for both the negative and positive cables. Well if the bullet connector is not making good contact then you will get the problem you described. It can be just fine one moment, then you hit a little bump or make a turn and then it isn't. Next thing you know the battery light comes on. So.........maybe you have a problem with the connections some where on your car. Are the connectors on the battery terminals properly tightened down? Are the battery terminals clean? Is the ground wire loose? How about the cable to the starter, is that connected properly? Things like that which can be easily over looked. So before you start on tearing out all your hair :D have a good look around at the connections.
     
  9. 87rari

    87rari Rookie

    Apr 29, 2007
    3
    Maryland, USA
    Thanks for all the replies! A new battery was put in after the original alternator failure, so that's probably not causing the problem & the battery connections are tight.

    The other eletrical connections and the diode assembly sound like good leads. I'll drag the car back to FoW and have them fix it right. This information should help pinpoint the problem...

    ...or perhaps it is the mystery voltage drop spot that's causing the problem! In which case I'll have to find a new route! :)

    Thanks!

    Mike
     
  10. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
    Full Name:
    Paul
    I read on the internet that Fermilab Particle Accelerator in Illinois was going to shoot neutrinos through the earth towards your area yesterday as some kind of high energy particle physics experiment with the University out there. Crazy.
     
  11. Ken

    Ken F1 World Champ

    Oct 19, 2001
    16,078
    Arlington Heights IL
    Full Name:
    Kenneth
    Your symptoms are classic dying alternator VR. At least that's what mine did after I ran the car without the battery connected (Don't do that! LOL). It lasted intermittenty a few weeks until I replaced it. YMMV.

    Of course, it could be a bad connection somewhere too.

    Ken
     
  12. LarryS

    LarryS Formula Junior

    Nov 14, 2003
    302
    Fremont, CA
    Full Name:
    Larry S
    +1
    and
    I always add a ground wire when working on any Ferrari component.
     

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