My QV started having fits. It sputters, spits then | FerrariChat

My QV started having fits. It sputters, spits then

Discussion in 'Mondial' started by srephwed, Jul 21, 2018.

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  1. srephwed

    srephwed F1 Veteran
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    #1 srephwed, Jul 21, 2018
    3years ago I put a 3.2 and XDI ignition in my QV. Till now it has been flawless. I am hoping someone may have had a similar issue. It runs fine then will start missing and sputtering a little. Idle drops 100 rpm. Then it will make a single pop or backfire in the intake and then run perfect again. Idle rpm up 100. Then it will take another fit in a while and repeat the cycle. I suspect electrical because of the backfire that corrects the problem for a while. Thanks in advance for any ideas.
     
  2. StuR

    StuR Formula Junior

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    #2 StuR, Jul 21, 2018
    Last edited: Jul 21, 2018
    As If you hadn’t replaced it have you done the same sort of checks (except for where stuff is replaced)?

    I say that in terms of plugs and plug wires as I think XDI (and definitely XDI2) make a point of pointing out how the system can (relatively) shorten the life of these components and the problems that they can induce. Wondered if you’d looked for carbon tracking or had the plugs out?

    I think bad grounds would be more general (or have melted someone), but would also double check those maybe?


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  3. srephwed

    srephwed F1 Veteran
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    #3 srephwed, Jul 21, 2018
    New plugs. Wires seem ok. The biggest mystery to me is the single pop in the intake and it runs great.
     
  4. spicedriver

    spicedriver F1 Rookie

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    #4 spicedriver, Jul 21, 2018
    Pop is a misfire.

    Check the actual resistance of the wires from the plug end to the electrodes in the cap. While the cap is off, check for signs of arcing inside the cap, and around the rotor. Could also be a fuel mixture problem. Common faults are clogged injector screens, and clogged WUR screens.
     
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  5. srephwed

    srephwed F1 Veteran
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    #5 srephwed, Jul 21, 2018
     
  6. srephwed

    srephwed F1 Veteran
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    #6 srephwed, Aug 4, 2018
    plunger for flap in intake was not operating freely. I guess the single backfire would blow it back into place and run ok for a while. I have my car back now.
     

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