The Fuel Pump, upon failure, can affect the sound of an engine; it can make strange noises that show it has a problem with delivering fuel. When a pump cannot keep up with the pressure required to function correctly, normally around 40 to 60 PSI on a standard setup, then the fuel flow to the engine becomes interrupted and it causes the engine to run lean. That lean condition can also result in misfires or poor combustion, giving an uneven, rough sound of the engine either at an idle or when acceleration occurs. Automotive studies indicate a 10 percent fuel pressure loss may increase the chances of noisy engines by approximately 20 percent as the engine would then be unable to overcome the deficiency of fuel.
Besides affecting the sound of the motor, a faulty fuel pump itself is able to make its noises apparent. Typically, a worn or failing pump will make a whining or buzzing noise in the area around the fuel tank, which indeed could mean it's working harder than usual while supplying fuel. Many mechanics relate this sort of noise with an imminent failure of the pump, especially for those vehicles that have more than 100,000 miles and where wear on internal parts should be expected.
Irregular sound of the engine might also be because of fuel pump relay failure. The fuel pump relay is responsible for regulating power to the pump. In the event of a relay failure, the power supply to the pump becomes intermittent as would also the correct flow of the fuel. This irregularity therefore affects the engine's ability for consistent revolutions per minute, thereby leading to variable sounds, particularly during the time of idling or when driving at low speeds.
Poor quality or contaminated fuel also adds to the stress on the fuel pump, hence affecting the sound of the engine. The dirt or other stuff in the fuel line will make the pump work harder, and that could not only stress the pump but may cause an irregular combustion of fuel, making a rough sound on the engine. Such situations hardly occur when regular maintenance of the fuel filter is carried out because, with a clean filter, it reduces the workload of the pump, and thereby the facility of smooth fuel flow is obtained.
Monitoring these symptoms and following proper maintenance of the Fuel Pump will help in avoiding abnormal sounds of an engine and further extend the life cycle of the pump along with its components.
