Mondial - 7 out of 8 pistons ! | FerrariChat
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Mondial - 7 out of 8 pistons !

Discussion in 'Technical Q&A' started by Mondy, May 1, 2009.

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  1. Mondy

    Mondy Rookie

    Mar 27, 2009
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    Andrew
    #1 Mondy, May 1, 2009
    Hi all I have a Mondial QV and you may recall I had a query (ECU) some weeks ago. Thanks to this FANTASTIC forum I located an ECU from one the FC members. This forum is invaluable ! Well the ECU is fitted but the wire loom going in to the ECU is pretty shredded. It seemed that the plug was wrongly wired and has been reversed by my mechanic BUT only 7 out of the 8 pistons are running. Changed dist cap and leads, but still no luck. Looking for an auto electrician but any ideas in the meantime. Need this car back on the road for the summer. Thanks for reading !!
     
  2. f308jack

    f308jack F1 Rookie

    Jun 7, 2007
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    Jack Verschuur
    #2 f308jack, May 1, 2009
    Unless you have a plug not firing, you have another than an electrical problem.
     
  3. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
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    #3 Artvonne, May 1, 2009
    Last edited: May 1, 2009
    Does it have any compression? It may seem a dumb question, but its really the starting point. When asked about compression in a recent poll, 7 out ot 8 pistons said they like to have some :)
     
  4. Mondy

    Mondy Rookie

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    #4 Mondy, May 2, 2009
    Thanks F308Jack but can you add to your comment or is it just speculative ?
     
  5. rustybits

    rustybits F1 Rookie
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    Jan 28, 2007
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    #5 rustybits, May 2, 2009
    Last edited: May 2, 2009
    Compression is one of the three things you should check. If you definately have fuel then it would only leave spark. Pull the plug from the dead cylinder and with the plug lead reatached rest it so that it's earthing on the engine somewhere. Get someone to crank the engine while you look for a spark.
     
  6. cockrill

    cockrill Formula 3

    Jan 23, 2008
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    #6 cockrill, May 2, 2009
    Before pulling the plug to check for spark, purchase an inductive spark tester. It's a little pencil shaped tool that you hold against your spark plug wires. If there is power going through the wire, the tool's light will flash. You can also use a timing light to do the same thing, but you have to have a power source for the timing light. The spark tester costs less than $10.
     
  7. f308jack

    f308jack F1 Rookie

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    #7 f308jack, May 2, 2009
    Not speculative.

    You need to first determine if the plug on the dead cylinder actually fires, suggestions on how to do that above.

    If it doesn't fire, swap the plug. (You said caps and wires are new, but are they good? New parts can fail too.)

    If it does fire, you have to dig deeper. Do a compression test and see what you find.

    If you have good compression and spark, you have a fuel delivery problem to that cylinder, which could basically only be the injector.

    If you have low or no compression, you have bigger trouble.

    Hope this helps you on your way!
     
  8. Artvonne

    Artvonne F1 Veteran

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    #8 Artvonne, May 2, 2009
    Anytime I have a question and have a plug out, I often take the compression just for peace of mind, kinda like taking BP. And you dont even have to pull out the rest of the plugs, just disable the ignition and crank it 5 pumps, if it makes anything over 100 it will run. That is NOT to say 100 is okay, its just that without pulling all the plugs you cant really expect to get a high reading. If its near zero you can stop looking for other possibilities, its a mechanical problem, and you should go ahead and do a leakdown to confirm it. Saves a lot of screwing around looking for a needle in a haystack that may not exist.
     
  9. Mondy

    Mondy Rookie

    Mar 27, 2009
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    #9 Mondy, May 4, 2009
    Thanks for responses so far - I will try these but just wanted to be prepared for the worst - what does it mean if there is no pressure in the piston ?
     
  10. Modeler

    Modeler F1 Veteran

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    #10 Modeler, May 4, 2009
    At least a valve job involving removing the head. At worst a rebuild.
     
  11. Mondy

    Mondy Rookie

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    #11 Mondy, May 16, 2009
    Thanks for all your responses - problem was one of the Flywheel contact pegs had sheared off !! Back on the road now.
     

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