The bad fuel pump drastically decreases fuel efficiency because the engine does not get the optimum quantity of fuel. In addition, fuel pumps always maintain the same pressure on the fuel flow to feed the fuel injectors with sufficient and constant flow. Normally, a conventional vehicle would be running in the range of 40-60 psi, while it may differ from one car model to another. As a result, malfunctioned fuel pumps lead to drops in fuel pressure, hence poorly feeding fuel to the engine. This can lead to incomplete combustion, whereby the engine doesn’t get enough fuel to operate at its optimal level. This directly affects fuel economy. The U.S. Department of Energy reports that improper fuel delivery can decrease fuel efficiency up to 10%, quite a significant reduction with the average cost of gasoline.
For example, a 2017 Ford F-150 with a malfunctioning fuel pump can experience a 5-10% decrease in MPG, based on data from the Environmental Protection Agency (EPA). The drop in fuel efficiency is normally felt more during acceleration or when the vehicle is under load, where the engine struggles to overcome the reduced fuel flow. According to Bosch Automotive, just a 10% reduction in fuel pressure can lead to up to a 15-20% loss in engine performance, which directly affects fuel consumption.
Aside from decreased fuel efficiency, other possible consequences of a malfunctioning fuel pump are engine misfires, stalling, or hesitation, further adding to increased fuel consumption. As the engine tries to compensate by pumping in more fuel, it may be overdoing it and end up burning more fuel than it actually needs to achieve that particular performance. This condition quite often results in the running rich of the engine, which, apart from reducing fuel efficiency, can also increase harmful emissions.
According to a report by the National Renewable Energy Laboratory, NREL, if a fuel pump goes bad, other crucial components within the fuel system could suffer long-term damage, including fuel injectors and pressure regulators. If these components are damaged by irregular fuel supply, it increases the cost of repairs significantly; at times, up to over $1,000. This, therefore, underscores the need for timely fuel pump maintenance to avoid further damage to the engine and the fuel system as a whole.
In modern vehicles with advanced fuel injection systems, a faulty fuel pump can have an even more pronounced effect on fuel efficiency. Direct injection systems, for example, rely on highly precise fuel delivery to achieve optimal combustion. A malfunctioning fuel pump can disrupt this precision, leading to inefficiency and increased fuel consumption. According to the Society of Automotive Engineers, direct injection vehicles may lose 10-15% of fuel efficiency when the fuel pump is not working properly.
It will conclude that a faulty fuel pump can directly and measurably affect fuel efficiency since it interferes with the proper supply of fuel to the engine for incomplete combustion, hence poor engine performance. This can result in a loss of up to 10-15% in fuel economy, depending on the severity of the problem. For more on high-performance fuel pumps, log onto Fuel Pump.