Audi Volkswagen Fuel Pump Assy 4L0919087A

A fuel pump is usually electric and located inside the fuel tank. The pump creates positive pressure in the fuel lines, pushing the gasoline to the engine. The higher gasoline pressure raises the boiling point. Placing the pump in the tank puts the component least likely to handle gasoline vapor well (the pump itself) farthest from the engine, submersed in cool liquid. Another benefit to placing the pump inside the tank is that it is less likely to start a fire.

Though electrical components (such as a fuel pump) can spark and ignite fuel vapors, liquid fuel will not explode (see flammability limit) and therefore submerging the pump in the tank is one of the safest places to put it. In most cars, the fuel pump delivers a constant flow of gasoline to the engine; fuel not used is returned to the tank. This further reduces the chance of the fuel boiling, since it is never kept close to the hot engine for too long.

An advantage of an electric fuel pump is reduced fuel consumption because it does not have the resistance associated with a mechanical drive and because the fuel supply can be monitored more accurately by the electronic control unit (ECU). Some of the symptoms of a fuel pump failure includes Rising Temperature, Surging, Engine Sputters at High Speeds, Reduced Mileage and sometimes the Engine wonƒ??t even start.