w176 A180 fuel comes out when refueling
My w176 A180 has a problem when refueling. When refueling the car, excess pressure builds up in the tank and fuel comes out of the fuel pipe.
Where do you think the problem is?
Any help would be massively appreciated.
- Ventilation System: The most common reason for this problem is a fault in the fuel tank ventilation system. If the tank isn't venting properly during refueling, pressure builds up, causing fuel to overflow.
- Blocked Ventilation Lines: Ventilation lines or hoses that are clogged or blocked could restrict the airflow, preventing proper ventilation of the fuel tank during refueling.
- Charcoal Canister: A malfunctioning or saturated charcoal canister, which is part of the evaporative emission control (EVAP) system, can cause pressure buildup if it fails to absorb fuel vapors properly.
- Check Valve Issues: Malfunctioning check valves in the fuel tank or EVAP system can hinder the release of pressure, leading to fuel overflow.
- Faulty Fuel Tank Pressure Sensor: In some cases, a faulty fuel tank pressure sensor might inaccurately measure pressure, leading to improper venting.
- Fuel Filler Neck or Cap: Damage or blockage in the fuel filler neck or a faulty fuel cap might disrupt the airflow, causing pressure to build up during refueling.
- Inspect Ventilation System: Check the ventilation lines, hoses, and connections for blockages, leaks, or damage.
- Check Charcoal Canister: Verify if the charcoal canister is saturated or malfunctioning. It might need cleaning or replacement.
- Examine Check Valves: Ensure check valves in the fuel tank or EVAP system are functioning correctly.
- Inspect Fuel Filler Area: Check for any damage or blockage in the fuel filler neck and confirm the fuel cap is in good condition and properly sealing.



