Yes, excessive fuel consumption can indeed result from a faulty fuel pump. When the fuel pump malfunctions, it results in the engine either being over- or under-supplied with fuel. The tendency when the pump delivers excess fuel is to make the engine run rich, meaning it doesn’t burn out completely. Consequently, this makes the engine use much more fuel than what was required. Studies indicate that a car with a faulty fuel pump may increase fuel consumption by up to 20% compared to those with functional fuel pumps.
For example, a high-pressure fuel pump can flood the engine with too much fuel, causing increased fuel consumption especially during acceleration. Sometimes, a malfunctioning fuel pump may bypass fuel around the engine’s fuel injectors, directly pumping it into the exhaust system, which further lowers the efficiency of the engine. One example comes from the repair manual of a 2005 Toyota Camry, showing how excessive fuel may raise fuel consumption by 30-40 percent and thus considerably raise the operating costs for the owner.
Moreover, when a fuel pump fails to supply fuel at the proper pressure, the engine may not be able to maintain the correct fuel-to-air ratio, leading to poor fuel economy. According to the U.S. Department of Energy, an engine with improper fuel pressure due to a failing fuel pump can raise fuel consumption by 10-15%, especially in heavy acceleration or towing situations. This is more evident in cars with fuel-injection systems, which require consistent fuel flow and pressure to function optimally.
In 2019, a case was reported in an Audi A6 model where the low-pressure function of the fuel pump resulted in increased fuel consumption by as much as 25% on long journeys. A clogged fuel filter, which usually comes with a deteriorating fuel pump, can further worsen the situation by reducing the pump’s ability to deliver fuel properly. This is because when the filter is clogged, the fuel pump has to work harder to push fuel through the system, using more energy and increasing overall fuel consumption.
A faulty fuel pump can promote excessive fuel consumption in different ways, such as by marring the correct air-fuel ratio or misfiring an engine. This can make a fuel system that does not meet up to the demand of the engine over-consume more fuel as compensation for performance weaknesses. For example, a malfunctioning Bosch fuel pump on a BMW 3 Series model has been shown to increase fuel consumption by 18% due to the engine’s inability to operate at peak efficiency.
Additionally, when a faulty fuel pump is left unattended, the increased consumption of fuel does not only increase operation costs but also may cause damage to the engine over time. The replacement of a faulty fuel pump and proper maintenance of the fuel system will reduce fuel consumption and increase the life of the engine. The replacement cost of a fuel pump generally ranges from $300 to $1,200, depending on the make and model of the vehicle.
A good working fuel pump will keep the fuel economy at its best. If the fuel consumption of your car increases, you need to take it to a mechanic for fuel pump checking. All these issues can be avoided by doing routine maintenance of the fuel system, such as changing the fuel filter and using good quality fuel. To know more about the high-quality replacement parts, log on to Fuel Pump.