456GT 1995 missing valve on vacuum line | FerrariChat

456GT 1995 missing valve on vacuum line

Discussion in '456/550/575' started by sully456, Feb 12, 2017.

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  1. sully456

    sully456 Rookie

    Feb 21, 2011
    40
    New Zealand
    Full Name:
    Steve O'Sullivan
    #1 sully456, Feb 12, 2017
    Last edited by a moderator: Sep 7, 2017
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
    Full Name:
    Brian Crall
    It is an air injection cutoff valve. Don't drive the car until it is fixed. If it allows air into the exhaust after warm up the O2 sensors would richen the mixture and destroy the catalytic converter.
     
  3. rviani

    rviani Karting

    Jun 22, 2005
    73
    NJ
    Full Name:
    Ron Viani
    The damaged valve is used during a cold start to route air from the compressor #1 on the diagram to the exhaust manifold. It is opened when vacuum is present at the attached small vacuum line. This allows air from the compressor to enter the exhaust manifold for a short period (generally a few minutes) until the engine is warmed and the vacuum control valve (#13) is closed by the ECU. Since all this only happens when the engine is cold the damaged valve typically will not effect normal operation.

    I had exactly the same problem ( the valve is in a very exposed position) many years ago which caused me to fail an emissions test. The damage to the valve you show effectively leaves the line to the exhaust open to the secondary air valve (#5) which apparently allows it to pull in a small amount of ambient air between exhaust pulses. The added air caused my car to fail on high NOX.

    I was able to identify a replacement valve which was a Pierburg #7.20605.00 I purchased from Hella Inc. Peachtree GA used I believe on a Volvo. As I recall it required some parts be interchanged between the damaged and new valve to duplicate the Ferrari application. Depending on your situation it may be easier to live with it as is or simply disable the entire system.

    If you need further help PM me at [email protected].
     
  4. deanhalter

    deanhalter Formula Junior

    Dec 27, 2008
    357
    Norco, CA
    Full Name:
    Dean Halter
    Good call on not driving the car, ask me how I know...

    I have a spare if you need it, PM me
     
  5. sully456

    sully456 Rookie

    Feb 21, 2011
    40
    New Zealand
    Full Name:
    Steve O'Sullivan
    Thanks for the comments - I have found a replacement.

    On another note - removed center exhaust resonator, replacing with straight pipes. The sound at idle rpm is throatier with a little burble.
    No real noise level difference at speed inside the cabin. But now you know there is something special under the bonnet.
     
  6. MotoMeccanica

    MotoMeccanica Formula Junior
    Silver Subscribed

    Aug 21, 2006
    433
    Calgary Alberta
    Do you still have stock mufflers? I you change those, like I did with Tubi's and straight pipes, you will experience something very different.

    Scott
     
  7. sully456

    sully456 Rookie

    Feb 21, 2011
    40
    New Zealand
    Full Name:
    Steve O'Sullivan
    I have standard rear mufflers. So just a little extra sound at idle with the center resonator removed.
     
  8. nettwerkjohn

    nettwerkjohn Karting

    Mar 6, 2015
    114
    Waikawa, Picton 7220
    Full Name:
    John Phillips
    It's worth putting cat delete pipes in as well...
     
  9. ohbeaver

    ohbeaver Rookie

    Apr 8, 2011
    36
    Fort Worth, Texas
    Full Name:
    Olin Beaver
    I have a pair of Braden delete pipes if anyone is interested. I tried them on my 2001 456m with Novalari mufflers and it was too loud for me. They are $850 from Braden and these are like new. Make me an offer if you are interested. It really changes the sound and are easy to install.
     
  10. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,985
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Olin- Are those cat delete pipes or center muffler delete pipes? Different animals. Incidentally, Bradan comes from the name of the two principals, Brad and Dan. You need to subscribe and put an ad in FerrariAds above.
     
  11. ohbeaver

    ohbeaver Rookie

    Apr 8, 2011
    36
    Fort Worth, Texas
    Full Name:
    Olin Beaver
    Thanks Taz,
    My mistake, what I have are the two straight pipes that replace the center muffler.
    Thanks also for the info on where to advertise. I will subscribe and post.
    Kindest regards,
    Olin
     

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