A vehicle fuel pump is needed to maintain adequate fuel (gasoline) flow to a vehicle's engine. Problems with fuel pump function can cause a variety of engine symptoms. What follows is a brief description of the most common signs and symptoms of a faulty fuel pump.
Hard to Start
You can blame the fuel pump many times if a car is hard to start. A car fuel pump is responsible for pumping gasoline from a car's gas tank and sending it directly to a car's engine. A faulty fuel pump may lack the strength to pressurise the gasoline adequately, resulting in a weak fuel flow that makes engine starting difficult.
If a faulty fuel pump loses its ability to pump fuel at all, a vehicle will experience a no-start condition. Gasoline is necessary for engine starting and combustion; a vehicle's starting system ignites gasoline and air in a vehicle's engine to produce starting. A car can't start if it can't get gasoline where it needs to be.
Besides starting a vehicle, a fuel pump is responsible for maintaining a constant stream of gasoline to a vehicle's engine. If this fuel flow fluctuates wildly, engine performance will suffer. A vehicle that frequently stalls during operation is normally the result of a fuel pump that fails to maintain a steady fuel flow or pumps and then stops pumping for a brief period.
Similar to engine stalling, engine surging involves a situation where too much engine fuel is squirted into a vehicle's engine. A faulty fuel pump may work fine for a period of time but will often overpump and send too much fuel into an engine, thus causing a brief period of acceleration or surging.
A car that hesitates fails to accelerate smoothly and efficiently. A fuel pump needs to function (pump) properly for a car to accelerate normally. A faulty fuel pump can cause a car to hesitate, again, if it fails to maintain a steady fuel flow. Slight fluctuations in fuel pump action causes a ripple effect on the fuel stream that is sent to an engine. This results in small moments of engine hesitation as normal fuel flow is interrupted by small moments of inadequate fuel flow.