89 Mondial T not firing on 5-8 | FerrariChat
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89 Mondial T not firing on 5-8

Discussion in 'Mondial' started by Vonbarron, Apr 6, 2024.

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  1. Vonbarron

    Vonbarron Formula 3
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    #1 Vonbarron, Apr 6, 2024
    Car was running a bit shakey, no power. No cel lights. Found one 7.5 fuse blown, replaced it, and reset the ECUs. Ran really great, drove great for about 30 minutes and that fuse popped. It now pops immediately. Have traced it to a brown with white stripe wire heading out to the engine somewhere. I’m assuming it’s grounding. I have the workshop manual but no proper wire diagrams, searching here has come up dry. Anyone?
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  2. Vonbarron

    Vonbarron Formula 3
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    #2 Vonbarron, Apr 6, 2024
    Oh and the tach works fine, I’ve read somewhere that it sometimes doesn’t work when the left side is dead
     
  3. Vonbarron

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    #3 Vonbarron, Apr 6, 2024
    Found an old post by Lino in 2011, Steve to the rescue with colors and Fuses, turned out to be a grounded fuel pump, I have a new place to look
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  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #4 Steve Magnusson, Apr 6, 2024
    Yet another post that I don't remember making ;), but it was some years ago. Certainly could be a fuel pump going south (with the known problems of 348/Mondial t fuel pump rubber decomposition/ingestion), but a 7.5A fuse just still seems very puny to me. In the intervening years, I've obtained copies of Mondial t OMs and the Mondial t WSM -- both show the fuel pump fuses being near the Motronic ECUs, but, surprisingly, neither discloses what those fuse current value should be. I know the CIS fuel pump pressure is about 5.5 bar and that fuel pump draws ~10A and typically has a 15A fuse for protection, and now know that the 348/Mondial t Motronic nominal fuel pressure is around 3.8 bar -- so would think that fuel pump would draw something like 6~7A --- so a 7.5A fuse seems puny.

    I'd suggest that you measure the current that each fuel pump is actually drawing when running to see if they are about the same or very different.
     
  5. Vonbarron

    Vonbarron Formula 3
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    #5 Vonbarron, Apr 8, 2024
    19633500GT, paulchua and JimboMondial like this.
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #6 Steve Magnusson, Apr 8, 2024
    Always good when it's a simple fix, but are you saying that the aluminum panel was cutting thru the insulation of the +12V wire, or are you missing the protection terminal boots, 54, here:

    https://www.ferrariparts.co.uk/diagram/ferrari/mondial-t-coupe-cabriolet/012-fuel-pump-and-pipes

    or were those terminal boots, 54, present but torn up/damaged, too?
     
  7. Vonbarron

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    #7 Vonbarron, Apr 8, 2024
  8. Vonbarron

    Vonbarron Formula 3
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    #8 Vonbarron, Apr 8, 2024
    Today I hammered it all back into shape, welded all the elongated holes, welded some pinholes in the rest of the aluminum and is now in black paint. Ill add silicon pad in the pump area in case the panel ever gets crushed again
     
    rob and 19633500GT like this.

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