No Fuel tank venting??
 

124 ,88 300E, fueled car early in the morning and came home.went to go out later that morning and the car had a heavy fuel smell, interior and trunk.
So I opened the fueling cap and out came about a quart of fuel under pressure.
I have been having this problem lately when I open the cap to refuel there is a great deal of pressure behind the cap when opening reguardless of the quantity of fuel remaining in the tank.
Should the fuel tank be under so much pressure?
Could I have a problem with the vapor recovery system?
The car has the original fuel cap which is a non vented type.
where is the tank vented to? ,and where is the vapor recovery canister located I have never seen one on this car.................Thanx John:confused:

it has a vent, but no idea where on your car. maybe in line with the filler pipe? should have a check valve too.

There is a vent canister behind the left front fender. It's very likely your problem. PN:A1244700359