ML 350 won't fill/gurgles during fueling
 

I'm helping a friend fix his 05 ML350. Besides a few things I fixed already, it won't take fuel.

I took it to the gas station, takes a dollar than klicks. The fuel is violently gurgling enough to splash out of the filler neck.

I think the system works by (using a pressure sensor on the filler neck) to open the canister vent valve to allow fumes/air to vent out.

Any ideas or pointers on this issue? Thanks

Have you tried rotating the gas nozzle 180 degrees?

I don't know the ML specifically but 94 - 00 W202 C class cars can have this problem and maybe the same solution as the ML ( RE vent not opening. )

In the mid 90's a customers Oldsmobile suddenly quit taking fuel. These have a basic fill and vent tube system so loss of fill is odd. I pulled the fill tube and found a gas pump weights and measures certification sticker blocking the fill tube roll over check valve. It was a round sticker that someone has folded to a point than inserted in the gas pump nozzle for the next unsuspecting person to use.

If no other source of fill restriction is found, maybe a fuel additive cap ending up in the fill.