A whining noise from a fuel pump usually means a problem with the pump itself or the fuel system. Usually, this noise happens because the pump is failing at pulling in fuel to the fuel rail properly, and this could be caused by a number of different reasons. A common cause, in other words, is not having enough fuel in the tank, which makes the pump work harder, and generates more friction and noise. In fact, as the National Automotive Service Task Force (NASTF) explains, fuel pumps are designed to operate with at least one-quarter tank of fuel. But if you start running on low fuel, it could make your fuel pump heat up, causing a higher pitch whine as it attempts to maintain pressure.
An old or bad pump can also be another cause of a whining fuel pump. The internal workings of the fuel pump (the motor, the bearings, etc) can wear out over time. Such wear increases pump friction and noise, in turn leading to poor operating performance. In a report published in 2019, the Automotive Maintenance Association reported that 15 percent of cars over 100,000 miles had owners complain of whining sounds from their fuel pumps. As the pump wears out, it becomes less efficient, and the whine grows louder.
The quality of the fuel is also very important. “Bad quality or contaminated fuel can block the fuel pump and/or fuel filter, which may require the pump to work overtime to push fuel through the system.” According to the American Petroleum Institute (API), contaminants in the fuel can plug up the fuel filter and the pump, resulting in higher pressure, which results in whining noise. The problem is more prevalent in older cars that have been using cheap fuel or haven’t really had their fuel system maintained.
A fuel pump whining sound can also be caused by a blockage or restriction in the fuel line. In the case the fuel filter is blocked, the pump will have to work harder to move the fuel through the system, which causes additional noise. According to the U.S. Department of Transportation (DOT) clogged filters or fuel lines can account for as much as 20 percent of fuel pump failures. This blocking inhibits the flow of fuel, causing a high-pitched sound of the pump making effort to augment the weaker flow.
For automotive experts like James Carroll, an auto technician with more than 25 years of experience, paying attention to a whining fuel pump is critical: “This whining noise could be one of the early symptoms that the fuel pump is beginning to fail. Neglecting it could lead to worse issues, such as pump failure, reduced fuel efficiency or even engine stall.”
In such instances where the whining does not go away, it might be better to check the Fuel Pump and the fuel system so that it is working fine and does not damage the vehicles engine. Regular maintenance such as checking the fuel level, changing the fuel filters, and using high-quality fuel can avoid the whining noise and may increase the life of the pump.