Can a Bad Fuel Pump Cause Excess Fuel Consumption?

A faulty Fuel Pump will often cause excessive fuel consumption arising from the inefficiency in the fuel delivery system. The fuel pump is supposed to maintain a constant and proper flow of fuel to the engine. If the pump goes bad, it will either over-feed or under-feed fuel to the engine, which consequently affects fuel efficiency.
The Fuel Pump may fail to regulate fuel pressure properly when it starts to fail. This causes over-fueling or under-fueling. In cases of over-fueling, the fuel injectors may pump in more fuel than required, making the air-fuel mixture richer. The imbalance will force the engine to use more fuel in an attempt to balance out the excess intake of fuel. According to the U.S. Department of Energy, a rich mixture can lower fuel economy by as much as 25%, thus making vehicles burn more fuel than they are supposed to.

Another common problem that comes with a malfunctioning pump is the irregular flow of fuel, which makes the engine run erratically. This inconsistency often forces the engine’s computer system to compensate, which might involve adjusting the fuel-to-air ratio. According to the study conducted by Automotive Testing and Development Services, failure in fuel pumps results in a considerable decrease in fuel efficiency, mainly when the pressure of the fuel pump drifts away from the ideal 40 to 60 PSI at which the fuel is properly delivered.

If the filter of the pump is clogged or worn out, it restricts the amount of fuel that reaches the engine, and the system needs to work harder to keep up with performance. The increased workload means higher consumption because the engine needs to compensate for the lack of fuel.

A 2020 Consumer Reports study on fuel economy also suggested that a faulty Fuel Pump can result in an overall decrease in miles per gallon, adding that even small inefficiencies can add up over time. Replacing a bad pump can bring a noticeable improvement in fuel efficiency, reducing fuel costs by as much as 10-15%.

At its worst, a bad pump could mean stalling or a rough idle, which requires more fuel to keep the engine running. In that sense, this problem may well manifest while doing city driving, where the frequent stop-and-go traffic exerts extra stress on the engine. Any drop in fuel economy or drop in engine performance calls for inspecting and testing the Fuel Pump as soon as possible.

For further information on fuel pumps and the replacement or repairs, visit Kemso Fuel Pump.

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