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1.8T - hissing from fuel cap?

niggtv Mar 19, 2006

  1. niggtv

    niggtv Member

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    Hi,

    I have noticed that when the engine is running there is a loud hissing coming from the petrol cap on my 1997 A4 Avant 1.8T.

    If I push the filler cap in the hissing stops, but then the idle on the car drops and it doesnt tick over smoothly.

    I have tried swapping the petrol cap itself incase this was all that was worng, but that didnt solve it.

    One last thing, the car seems to be very slightly hesitant - I had thought this might be the MAF, but am wondering if it linked to this problem somehow.

    Any ideas guys? Cheers
     
  2. madvw

    madvw Active Member

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    probably will be. Most of them will show the check engine light if it detects a leak here. The vapor from the tank is now recirculated, rather than vented into the atmosphere.

    you say you've tried swapping the petrol cap, was it for a new oem one, or a replacement get you home jobbie?
     
  3. niggtv

    niggtv Member

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    I replaced it with the fuel cap from my mate's A4... they looked exactly the same.
     
  4. madvw

    madvw Active Member

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    strange. It sound like there may be too much pressure then.

    Does anybody know if the petrol caps have valves in? If so, what regulates the pressure in the fuel tank recirc?
     
  5. Kevint

    Kevint Active Member

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    I had a similar problem on an Astra once. The car would stall every now and then though.

    It turned out to be a blocked vent pipe which was connected to the neck of the fuel filler.

    Kev.
     
  6. niggtv

    niggtv Member

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    Cheers, sounds like it might be something like a vent pipe.

    Has anyone had this hissing problem on an Audi, or suggest any other possible causes?
     
  7. niggtv

    niggtv Member

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    Well, thought I would post up the solution incase anyone else ever has the same problem. It was the recirculation/solenoid valve, which is located near the airbox in the engine bay. Part number is 058 133 517.
     
  8. Daveiow

    Daveiow Member

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    did it sort out teh car being hesitant as well ????
     

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