You're at the gas station pumping gas when your pump suddenly shuts off after only a few minutes. You know that your gas tank isn't anywhere near full, but it shuts off anyway. You start pumping again and it shuts off again in the same way. This problem happens to everyone on occasion, but it shouldn't happen all the time. If you're having constant problems filling your gas tank because the pump keeps shutting off, here are a few reasons why and some solutions to the problem.
Poor gas tank or filler pipe design:
The reason why the gas pump shuts off is that it senses fuel or vapors in the filler pipe and it "thinks" that the tank is full. Some gas tanks and pipes are poorly designed or too narrow, causing gas and vapors to splash back up from the tank when gas is pumped too quickly. Most of the time, it only happens on some pumps and not others. Many people have good luck with taking the nozzle out and putting it back in at a different angle or moving the nozzle around.
Problems with your car's evaporative emission system:
Modern cars and gas pumps are designed to prevent fuel emissions from being released into the atmosphere. One part of this system is that you car is designed to capture these emissions and trap them in a charcoal canister before they are sent back to the engine for combustion. When one of these components is not working properly, it causes pressure in the tank to change and trigger the gas pump to stop pumping. Often, this problem will be accompanied by a lit "check engine" light on the dashboard signaling a need for you to get the system checked out.
Problems with the gas pump itself:
Sometimes, the problem lies not with your car, but the gas pump. It may pump too fast, have a bad sensor or mechanical issues. Just about every car owner comes across a problem pump once in a while. If you already have problems with your car's gas tank design or evaporative emission system, then you will have an especially hard time with these pumps. In these cases, your best choice is to move to another pump or try a different gas station.
If your car is having a frequent or constant problem with the pump shutting off before your tank is filled, and your "check engine" light is on, then see a mechanic, like Goodeal Lifetime Transmissions, to have your car checked out. The problem may be as simple as a bad switch, hose or damage to your filler pipe. All of these can be easily fixed or modified so that you won't have to worry about not being able to fill your gas tank.