Where are the major grounding points in the Modial? | FerrariChat

Where are the major grounding points in the Modial?

Discussion in 'Mondial' started by docvb, Sep 20, 2012.

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  1. docvb

    docvb Rookie

    Jun 6, 2010
    31
    #1 docvb, Sep 20, 2012
    Everyone's Mondial has bad wiring and bad grounds. But where are the major problem grounding points located? These cars are rather complex and I've rooted around quite a bit, but I really haven't seen many grounding spots yet. Maybe this is because I've yet to take the dash or console apart (yet). But it would help to be able to focus on a few high-probability targets to focus on. What's the best way to check for a dodgy ground point?

    Thanks

    1987 Mondial Cabriolet 3.2, 89000 miles (!), Rosso Pruno
     
  2. soucorp

    soucorp F1 Rookie

    Sep 20, 2011
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    Mike
    #2 soucorp, Sep 20, 2012
    Last edited by a moderator: Sep 7, 2017
    I would say you should be able to find a decent ground anywhere along the bus path.
    Usually a good ground can be found on any big metal bolt attached to any metal frame of the body. Unless you reverse the polarity from battery which I recently did on my Midget restore project and turned the ground live. A Homer Simpson 'Doh' moment for sure!
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  3. mg54

    mg54 Rookie

    Jan 12, 2005
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    Michael Gardner
    #3 mg54, Sep 20, 2012
    For the last few years, my check system board hasn't been right. i've changed bulbs, cleaned fixtures, just about everything...I cleaned every ground I could find....still not right..

    Finally, I found the main ground from the engine to the frame...I cleaned the heck out of it. The check system is like new. My fluctuating gas gauge is also perfect now!.

    It is about an inch wide, 8 inches long and is located on the passenger side of the car at the lower back of the engine below the engine coolant drain plug...look closely..mine was covered with grease, dirt...I also cleaned and sanded the connection points...good luck
     
  4. peterdavid911

    peterdavid911 Formula 3

    Apr 9, 2012
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    London, UK
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    Peter
    #4 peterdavid911, Sep 21, 2012
    Hi I have the exact same problem with my center check control panel, it has a mind of its own and have checked all bulbs too. The 2 illumination bulbs flicker randomly and noticed that one will turn on when the fuel filler is open and off when I shut it.
    Could you possibly post some pictures of the main ground to the frame that you method so I can try it. Mine is a 1987 uk right hand drive 3.2.
    Thanks, Peter.
     
  5. docvb

    docvb Rookie

    Jun 6, 2010
    31
    #5 docvb, Sep 21, 2012
    Modial, Mondial, Potato, Potatoe, my Dark Prune car is still a Rosso color!

    soucorp--thanks for the diagram. Already printed and laminated.

    mg54--Great point about the major ground points. These are the most likely to be the actual problem-makers. I will re-examine and preemptively rework the battery grounding and engine ground straps first before going after the others. Did you replace the engine ground strap or just clean up the junctions?

    I hope to avoid the creation of an entirely new grounding circuit wiring harness as others have done.

    Anyone ever have grounding problems from the engine subframe bolting junctions? This old girl probably has been disassembled and reassembled a few times and (living in Wisconsin now) there is likely some corrosion.
     
  6. soucorp

    soucorp F1 Rookie

    Sep 20, 2011
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    #6 soucorp, Sep 21, 2012
    Last edited by a moderator: Sep 7, 2017
    Oh yes, having a solid ground connection is something that I have come to know very well recently with my MG project car and my daily driver Sahara.

    My Jeep had starting problems a few months ago, I took it to dealer, they installed a new starter, drove home and same problem, intermittent starts. So I added a 4 gauge ground wire from the neg post of the battery to the alternator/engine bolt. Now my Jeep seems to start ever time and this is after the dealership thought they fixed the problem with a new starter, NOT !

    What tends to happen is that the ground connections may look ok, but the other end going into the engine may have corroded, rusted, or got loose.
    I suspect my Ferrari windows have poor ground connections as well, explains the slow windows or stop working windows. More testing on the window theory when I have time this winter.
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  7. docvb

    docvb Rookie

    Jun 6, 2010
    31
    #7 docvb, Sep 21, 2012
    regarding the Mondial 3.2 Electrical ground diagram:

    I am guessing the bold red lines are for Frame components and the smaller black lines are ground wires that congregate to a common ground point? Big spots would be in the rear pass. trunk by the MPEM box, by the door hinges, and so forth? Any hope with the numbering naming legend here?

    Using this convention, however, gives me the impression there should be an aux. ground wire that connects to the battery neg post, in addition to the big old black grounding wire that goes to the frame (bypassing the on/off disconnect in my car). Is this an incorrect conclusion? Anyone have this from the factory???
     

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