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hissing petrol cap and lumpy idle

Discussion in 'A4/S4 forum(B5 Chassis)' started by g60leigh, Feb 28, 2008.

  1. g60leigh

    g60leigh Well-Known Member

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    A bit of a grumble this one.
    On top of the airbox is a little valve. When i have it connected i have lumpy idle and can hear hissing from the fuel cap. If i disconnect it, it runs fine. I have been told it links to a charcoal filter and is something to do with fuel vapour purging. Does anyone know if it is needed? Should i replace the valve or leave it disconnected? ( while it is connected if you hit it it works ok for a short while)
     
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  3. Broken Byzan

    Broken Byzan Photographic Moderator
    Staff Member Moderator VCDS Map User quattro Audi A4

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    I have the same, i repalced the valve and its good now
     
  4. g60leigh

    g60leigh Well-Known Member

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    how much did it cost you? (and the stupid question- what is the part called?)
    Thanks
     
  5. Broken Byzan

    Broken Byzan Photographic Moderator
    Staff Member Moderator VCDS Map User quattro Audi A4

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    N80 or purge valve £46.75 plus VAT from VAG parts
     
  6. AUDI TURBO

    AUDI TURBO Member

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    anyone got a picture of this im sure my aeb 1996 a4 doesnt have this valve
     
  7. g60leigh

    g60leigh Well-Known Member

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    mine definately does
     
  8. Broken Byzan

    Broken Byzan Photographic Moderator
    Staff Member Moderator VCDS Map User quattro Audi A4

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  9. g60leigh

    g60leigh Well-Known Member

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    thats the bit but mine is situtated on the top of the air box (Under a plastic cover)
     
  10. Broken Byzan

    Broken Byzan Photographic Moderator
    Staff Member Moderator VCDS Map User quattro Audi A4

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    I dont have the cover is all. keeps the heat in too much IMO,lol
     
  11. olds_kool

    olds_kool Active Member
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    i snapped this bit the other day changing air filter, was wondering what it did as car seems ok without it, should i replace it straight away or can it wait a couple of weeks?
     

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