The pressure stability of the fuel system is directly related to fuel economy. When the original factory specification pump (such as Bosch 0580254 series) maintains a pressure of 58±0.5 psi, the fuel injection pulse width accuracy error is less than 1%. According to the SAE 2024 study, pressure fluctuations exceeding ±2 psi will cause the air-fuel ratio to shift by 4%. This leads to an increase of 0.6 liters in Fuel consumption per 100 kilometers for a regular 2.0L engine. Actual cases can be seen from the user data of Honda’s 1.5T Earth Dream engine. After replacing the low-quality Fuel Pump, the annual fuel cost increased by approximately 320 US dollars.
The efficiency decline of the worn pump significantly increases fuel consumption. Tests by the U.S. Department of Energy show that after 120,000 kilometers of use, the copper loss of the fuel pump motor increases by 18%, and the flow output drops from the designed value of 72 L/h to 65 L/h (a deviation of 9.7%), forcing the ECU to extend the fuel injection time compensation, consuming an additional 8% of fuel under urban conditions. The J.D. Power 2025 report indicates that vehicles with regularly maintained fuel pumps consume an average of 5.3% less fuel than those without maintenance, equivalent to saving 42 liters of gasoline per 10,000 kilometers.
Advanced pump technology enables active fuel savings, such as Delphi’s electronic variable displacement pump, which adjusts the flow rate as needed through PWM signals (reducing to 15 L/h at idle), reducing parasitic power loss by 87% compared to traditional mechanical pumps. After applying this technology to the BMW B48TU engine, the NEDC cycle fuel consumption was reduced by 4.2%, saving the owner $150 in fuel budget each year, and the pump body weight was reduced by 300 grams, enhancing the lightweighting benefits.
The pressure control accuracy optimizes the combustion efficiency. The direct injection system in the cylinder requires an ultra-high pressure of over 200 bar. The new piezoelectric Fuel Pump, through a response control of 0.01ms, optimizes the median fuel atomization particle size from 120μm to 20μm, and increases the combustion speed of the mixture by 30%. The real vehicle test of Mazda Skyactiv-X shows that when combined with a high-precision pump, the thermal efficiency can exceed 43%, reducing fuel consumption by 10% compared to traditional systems.
However, there is an economic critical point in the transformation. The purchase cost of the performance pump (such as the Walbro 450L) is 300 US dollars. Although the power is increased by 6% on the 2.0T engine, the fuel consumption is increased by 3%. The EPA calculation model shows that an annual driving distance of over 30,000 kilometers is required to achieve a two-year payback period. Ordinary users are more suitable for maintaining the original factory specifications to avoid performance imbalance.