Fundamentally, the design of fuel pumps is to be quiet; however, purring or mild humming noises usually occur, especially in high-performance or older vehicle models. Tolerance for noise from a fuel pump basically depends on the type, vehicle design, and general state of affairs regarding the fuel system. Most vehicle designs feature a fuel pump that is barely heard, especially in in-tank models where fuel itself acts to dampen the sound. However, during its operation, it is quite normal to hear a slight humming or whirring, especially while the vehicle is at an idle or under high load conditions.
A normally operating Fuel Pump usually gives out a noise level at approximately 40 to 50 dB, comparable to a quiet conversation. However, excessive noise-loud whining, rattling, or grinding-indicates there may be some malfunction. For example, a noisy pump can indicate a failing O-ring, clogged fuel filter, or low levels of fuel. If the Fuel Pump is not submerged enough in fuel, the pump has to work much harder, creating more noise and possibly shortening its useful life.
On the other hand, highly performance-based applications utilize louder external Fuel Pumps, such as the Walbro 450 LPH, due to higher flow rates and mounting outside the fuel tank. These are more effective at delivering fuel to large engines but can generate noise levels near 60 dB under load. This is quite normal for performance enthusiasts who regard this trade-off as increased fuel flow and horsepower support.
An example of this happened during the development of the Ford Mustang GT in 2018, in which several reports came up, stating that higher-flow fuel pumps fitted into supercharged forms of the car were much noisier. The noise, however, was within acceptable limits for high-performance vehicles where engine modifications often amplify the mechanical noises.
It can also be an indication of a problem within the Fuel Pump, as excessive noise or more so high-pitched whine. According to the words of David Vizard, an automobile expert, “Noises in fuel systems are usually early warning of larger issues”. If treated early, one can prevent costlier repairs or the failure of a Fuel Pump.
Other details concerning the diagnosis and care of your Fuel Pump log in at Fuel Pump.