05-05-2016, 04:02 AM
It's not just the angle at which you put the nozzle. There is a complex system in modern cars that seeks to absorb the gasoline fumes that are expelled as the tank fills. The tight fit of the filler neck around the nozzle is designed to force the fumes to go through the charcoal canister. The connection of the canister to the tank is itself not just a nipple off the top of the tank. There are roll-over valves built in to seal the opening if the car winds up upside-down. On my vehicle, a Ford Ranger, there is a solenoid valve in the vent line too. Not sure when that is supposed to be closed but if it breaks it could break in the closed position. Then there is the carbon canister itself and finally there is an air filter of sorts to keep dirt and bugs out of the system. There are multiple ways that the system can fail. The Ranger is notorious for such failures and mine takes forever to fill. You must just barely crack the nozzle open or it immediately shuts off. I have tried getting the roll-over valve out of the top of the tank but there is no room to work and it is glued in by 17 years of gunk.