The fuel pump in a vehicle pushes fuel from the tank to the motor. The unit usually sits in the tank of the vehicle using an electric powered motor and consists of an array of valves and spring that work in conjunction to create suction. This suction draws fuel into the pump which causes the return spring to push the fuel up into the lines creating pressure. (The unit pictured is intended for normal vehicles, vehicles demanding higher fuel pressure have more robust fuel pumps than the unit pictured).

The fuel pressure in the lines is not regulated by the pump itself, the pump will just pump to its maximum ability with the voltage provided from the vehicle. The fuel pressure is regulated down the fuel lines at the motor by a fuel pressure regulator also known as a FPR. The higher the voltage applied to the pump, the faster the pump will move and the higher the flow of fuel will be from the pump. Generally, a fuel pump will be part of an assembly which will also include a sending unit, level arm and screen filter.

The fuel pump may fail, over time, resulting in various engine-related/acceleration problems. A common symptom of a bad fuel pump is a stalling/hesitating/surging engine. Your vehicle may also find it difficult to start as there won’t be a sufficient supply of fuel from the fuel pump. You will find a decrease in the engine’s efficiency/performance. In extreme cases, the engine will not start at all.