GT4 ignition switch problem or ? Need help | FerrariChat

GT4 ignition switch problem or ? Need help

Discussion in '308/328' started by plugzit, Mar 5, 2020.

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  1. plugzit

    plugzit F1 Veteran
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    Dec 1, 2004
    7,667
    Redondo Beach, CA
    Full Name:
    Bruce Bogart
    With the ignition switch in run position (pos 2) I have 12v to coil. But, in start (pos 3) there is no 12v to coil!
    As a result, I have to separately switch the starter solenoid to start and run the car. Bad switch???? It's driving me nuts.
    I bought the car as a complete basket case, so didn't have the luxury of knowing any idiosyncracies beforehand. Any help appreciated.
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,039
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    What year/version 308GT4? Pretty sure that your symptom would condemn the ignition switch itself (if no modifications), but, IIRC, the early GT4 have a more complicated setup to switch out the ballast resistors during starting so that might up the chance that someone has done something strange, or maybe something in that more complicated system could fail that would cause your symptom. If you give year/version, I'd be glad to have a quick look at the schematic.
     
  3. lm2504me

    lm2504me Formula 3
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    Aug 26, 2004
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    Nipomo, CA
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    Richard
    #3 lm2504me, Mar 5, 2020
    Last edited: Mar 5, 2020
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
    Full Name:
    Brian Crall
    If it is a switch be careful of what you buy to replace it. There are Chinese knockoffs being sold that are junk. I got stuck with one for my own car and it would just shutoff driving down the freeway. The good ones are from one of the German suppliers and are marked accordingly on the back.

    I did get Ted Rutland back though. His GTC4 broke down in my shop with a bad switch and I installed the Chinese one he sold me.
     
    mike32 and plugzit like this.
  5. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
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    Mitchell Le
    This reminds me of a Maserati Biturbo I once foolishly owned.
     
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  6. plugzit

    plugzit F1 Veteran
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    Dec 1, 2004
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    Redondo Beach, CA
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    Bruce Bogart
    Thanks guys!
    It's a '75 US version. I hope it is just the switch, as it can be solved easily (kinda) with a few bucks.

    More like a Biturbo owned you! Me and Vince too! Arrrrrrrrrrrrrgh! :eek::mad::(
     
  7. lm2504me

    lm2504me Formula 3
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    Aug 26, 2004
    1,086
    Nipomo, CA
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    Richard
    Ebay item above is original German made Bosch item. I bought extras for my Duetto which uses the same switch contact block.
    The price is very good vs others.
     
  8. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,039
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    The schematic in your 100/74 OM shows you have the more simple ignition system design that always uses the ballast resistors = pretty strong sign that it is an ignition switch problem if you have +12V at the coils in Pos II, but don't in Pos III.
     
  9. Stephen B.

    Stephen B. Karting
    Silver Subscribed

    Nov 3, 2018
    101
    Full Name:
    Stephen Bailey
    Hey be nice. In addition to my 75 GT4 I also own a 87 Biturbo SI. Look at it like this, if you can figure out the on going electrical problems with a Biturbo all these other problems with a GT4 are of a minor concern. There is nothing like the wiring print for a Biturbo, if you can troubleshoot these you can fix almost anything. And yeah I love the damn thing--when nothing is inop or broken.
     

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