cannot trace fuel smell

Discussion in 'Engine' started by sraouf, Jan 16, 2020.

  1. sraouf

    sraouf New Member

    Messages:
    2
    Joined:
    May 19, 2015
    Car:
    S124 280E
    Can anyone help with tracing a faint raw fuel smell at the front of the engine bay behind the fan shroud between the air filter box and the block? Ive removed the air filter box and checked the fuel pressure regulator, the injector rails as well as the pipes/hoses around the fuel pump at the rear but cannot find evidence of a leak anywhere. The car is a 1993 S124 E280 with an M104 engine.
    Thanks
    Sam
     
  2. aybracers

    aybracers Active Member

    Messages:
    82
    Joined:
    Apr 29, 2008
    Location:
    London
    Car:
    1995 E320 Coupe
    Hi Sam,
    Had a similar thing a couple of years ago on my E320 coupe. Changed the tank but it didn't solve the problem. I turned out to be weeping from the top of the fuel lines (The part of the pipes next to the chassis) Once both the supply and return pipes were changed smell went away.
     
  3. OP
    OP
    sraouf

    sraouf New Member

    Messages:
    2
    Joined:
    May 19, 2015
    Car:
    S124 280E
    Thank you. Ill have a look!
     
  4. grober

    grober MB Club Veteran

    Messages:
    27,512
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    Could be the fuel tank evaporative system charcoal filter . This is designed to trap and burn fumes from the petrol tank. There's a line[ like a brake line but slightly thicker] from the tank at the rear runs to a charcoal canister filter under the passenger front wing [ its behind the wheel arch liner so you won't normally see it] to trap fumes. In turn this is connected to the inlet manifold and periodically the canister is evacuated by engine vacuum via a small solenoid valve under the bonnet controlled by the ECU. Any leaks or malfunction with this system might give a fuel smell--- the charcoal filter is supposed to be changed every 70k miles or 5 years but is often neglected.
    W124 Pressure in Fuel Tank

    Other possibility would be worn injector seals where they enter the manifold
     
    Last edited: Jan 22, 2020 at 9:12 AM

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