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400i running problem

Discussion in 'Technical Q&A' started by matt_4man, May 23, 2005.

  1. matt_4man

    matt_4man Rookie

    May 23, 2005
    5
    Please help, I have a fault that I am having problems solving. Its a 400i which starts and runs fine from cold but if turned off and started again whilst hot it is difficult to start and when finally does it runs badly, sound like its only on one bank. Seems to start and run again ok if left to cool.

    Thanks in advance for any suggestions.
     
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  3. andrewg

    andrewg F1 Rookie
    BANNED

    Sep 10, 2002
    4,667
    Chester, England
    Full Name:
    AndrewG
    Matt, where in the world are you?, has the car been ,modified to get it into the states?
    it sounds like some sort of vapour lock problem but without knowing more about the car................
     
  4. fletch62

    fletch62 Formula Junior

    Mar 8, 2004
    333
    Fairhope, AL
    Full Name:
    Larry Fletcher
    You have a PM
     
  5. Frank R. Masiarz

    Nov 10, 2003
    126
    Full Name:
    Frank R. Masiarz
    Hi.......

    If your Ferrari employs the same ignition module as the Boxer, I would suspect it. Consider installation of an MSD unit, after an examination of ignition system performance.

    Perform a search for "MSD" or "Boxer ignition" and you will find threads involving the problem in Boxers.

    Frank.........23005
    www.masiarz.net/bb_resource
     
  6. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    15,505
    The Cold North
    Full Name:
    Tom
    Fuel accumulator for one bank is not maintaining fuel pressure..Check to make sure they are not leaking internaly..(broken diaphram)
     
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  8. matt_4man

    matt_4man Rookie

    May 23, 2005
    5
    thanks for your replies

    I am in the uk ,
    already have MSD fitted,

    excuse my ignorance, where will i find fuel accumulator

    thank you
     
  9. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
    UK
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    Malcolm W
    #7 Ferrari_tech, May 24, 2005
    Last edited by a moderator: Sep 7, 2017
    Basically the 400i has two seperate injection systems (two of everything ) including the fuel accumulators on your car, they are located at the rear of the car in the area under the boot floor and are fitted between the fuel pump and the fuel filter. The problem could also be one of the fuel fumps not holding pressure (they have a one way valve fitted on the outlet side of the pump).

    You will neen a pressure test guage in order to check the fuel pressures, it may be easier to have it checked out by someone who has the correct equipment.

    The minimum fuel pressure must, after 10 minutes be 1.7 bar and after 20 minutes be 1.5 bar.

    Here's a picture of the general layout of the fuel system.
    Image Unavailable, Please Login
     
  10. matt_4man

    matt_4man Rookie

    May 23, 2005
    5
    Thanks for answering, (not doubting) just curious, why is this affected by engine temp, (or seems to be). Could it be corrected by just installing a one way valve in the fuel line when I determine which bank it is.
    thanks again
    Matt
     
  11. andrewg

    andrewg F1 Rookie
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    Sep 10, 2002
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    Matt, if you look in the yellow pages there is normally a couple of Bosch fuel injection service centre's listed, your probabley best taking the car to one of them for diagnosis
     
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  13. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
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    If it turns out to be the fuel pump one way valve, then yes Bosch will supply a valve instead of having to replace the fuel pump.
     
  14. matt_4man

    matt_4man Rookie

    May 23, 2005
    5
    Hi, I have today swapped the pumps and accumulators to feed the opposite banks but the problem remains on the right bank. Still fine when starting from cold and runs fine until turned off for more than a few minutes when hot. Any suggestions appreciated.
    thank you
     
  15. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
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    Malcolm W
    #12 Ferrari_tech, May 26, 2005
    Last edited by a moderator: Sep 7, 2017
    Okay, something else to check, have a look at the relay board and see if relay number 17 is fitted, if it is remove it and throw it away then retry starting the car. Basically this relay will make the cold start relays spray even under hot conditions.
    Image Unavailable, Please Login
     
  16. matt_4man

    matt_4man Rookie

    May 23, 2005
    5
    Unfortunately that seems to have no effect either. Another symptom is popping back through the inlet. Enough to blow off the rubber. I have also swapped the warm up regulators side to side to no avail.
     
  17. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
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    Full Name:
    Malcolm W
    Seems like the time has come for a full fuel pressure check and see what the results are.
     

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