dvnrbnsn

I have searched the forum for problems pertaining to 2004 E500 fuel problems but I have not found the one that I am currently experiencing. The problem that I am having is that when im at the pump gasing up the pump clicks off multiple times as if the tank was full when it is not, then gas spews from the tank as if it was full also. What is going on?

2slowcdi

On my Land Rover this happened and I had bent the air return line "tank vent" that went to the filler neck.

DanG2

Looks like you've got a blockage somewhere in your evaporative emission system. I can't find anything specific to Mercedes at the moment, but there's a generic description at http://www.aa1car.com/library/evap_system.htm . When you fill the tank with liquid, the vapors have to go somewhere, and if they can't get out through the vent system, they have to come back up the fill pipe, which results in the symptoms you're seeing.

The blockage could be could be caused by one of the controls not working properly, or it could be a kinked or plugged hose or pipe, or something in the charcoal cannister itself. It might be easy to find, or it might be a pain. If you've got a good shop I'd be inclined to take it there and let them find it.

dvnrbnsn

@DanG2 thanks for the info. Ill get it checked out.

konigstiger

Here is a diagram of tank & attachments 140 is filler neck, 150 is vent line to charcoal filter. I can send instructions for DIY vent inspection if you want – involves removing right rear wheel and fender liner.

dvnrbnsn

Yeah if you can send me instructions for the diy inspection that would be great!