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348 voltage drop

Discussion in '348/355' started by ginsuguy, Aug 5, 2008.

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  1. ginsuguy

    ginsuguy Karting

    May 4, 2006
    209
    #1 ginsuguy, Aug 5, 2008
    Need some help please. New high amp alternator installed in my 90 348. When a meter is put on ,and at idle, the reading is 13 and when the lights go on it drops to 11. The horn and ac drop it even further. Revs of the engine do little. Something is draining it or I am getting a false reading. Any experiences with this? I read that dino's had a fuse problem that caused this problem. Thanks in advance. I have been battling this for 5 weeks...
     
  2. Jeff Pintler

    Jeff Pintler Formula Junior

    Jul 20, 2005
    537
    Richland
    Full Name:
    Jeff Pintler
    #2 Jeff Pintler, Aug 9, 2008
    Make sure your battery is in good condition. If you are reading less than 13.5 volts under load then the new alternator could be bad. Check grounds between the alt and the motor and battery/chasis. Lastly, my 89 car has this funky single large connector under the air box that runs between the starter and the battery which the alternator may feed the battery. When I seperated the connection, there was all sorts of white arc residue. I didn't have a charging problem but it didn't look right so I replaced it with a new battery cable from Ricambi at $150 vs. Ferrari all new harness to alt for $1500. YMMV.

    Jeff Pintler
    89 348tb, 86tr
     
  3. PAP 348

    PAP 348 Ten Time F1 World Champ
    Lifetime Rossa Owner

    Dec 10, 2005
    100,228
    Mount Isa, Australia
    Full Name:
    Pap
    #3 PAP 348, Aug 9, 2008
    Sounds like your new 'high amp' alternator is f*cked. :):)

    Two things to check.......

    1-Remove battery and get it load tested.

    2-Remove alternator and get it bench tested.

    Check the battery 1st, as it is easier removing it. If the battery is ok, then take that alt back off and get it bench tested.
    It will be one or the other I reckon mate. I have seen it many times before.
     
  4. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
    Vegas+Alabama
    Full Name:
    Mr. Sideways
    #4 No Doubt, Aug 9, 2008
    Great suggestions above.

    Minor suggestion is to also check the tension on your alternator belt.

    For that matter, what voltage are you showing in your cigarette lighter with engine off, and with engine on?
     

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