Abnormal increase in fuel pump current is usually caused by the coupling of multiple factors, which directly affects the system reliability and energy consumption efficiency. When the mechanical resistance increases abnormally (such as impeller jamming or bearing damage), the power demand of the motor shaft increases by 42%. The measured results show that the operating torque of the needle roller bearing with deteriorated lubrication reaches 0.8Nm (the new part is only 0.25Nm), causing the working current of the Fuel Pump to exceed 18A (nominal value 12A±10%). The 2024 SAE research report indicates that 67% of fuel pump failures in oil sands mining trucks in Alberta, Canada, exhibit this feature, with a single repair cost exceeding $1,500.
The deterioration of the electrical system is one of the main causes. When the contact resistance of the plug-in component rises to 0.5Ω (the standard for new components is ≤0.05Ω), the voltage loss of the 12V system line reaches 6V. To maintain the same fuel pressure, the current output needs to be increased by 37%. Ford Technical Bulletin SSM 50155 confirmed that oxidized and corroded wiring harness terminals can expand the peak current fluctuation range from ±1.5A to ±5.2A, resulting in an 80% reduction in the lifespan of relay contacts. Data analysis of the Rio de Janeiro taxi fleet in Brazil in 2023 shows that the incidence of such faults in coastal high-humidity environments is 220% higher than that in inland areas.
The changes in the physical properties of fuel significantly alter the load characteristics. When transporting E85 ethanol gasoline (with an ethanol volume fraction of 85%), the internal leakage increases due to a 54% reduction in viscosity. To maintain a flow rate of 45L/min, the pump body needs to increase its speed by 25%, and the current rises by 19% accordingly. General Motors’ durability test report disclosed that the median current of the pump body using ethanol fuel rose to 14.8A after 100,000 kilometers (stable at 12.2A for the gasoline solution), and the brush wear rate increased by 300%. It is worth noting that the new regulations of the US EPA in 2025 require all Fuel pump to be compatible with biofuels, and the material alcohol resistance standard has been raised to ASTM D471 Level E3.
Design flaws cause excessive electromagnetic loss. Due to the eccentricity of the 0.03mm rotor of a certain brand of vane pump, the magnetic field distortion was caused, and the no-load current reached 7.5A (the normal value is 4A). The energy efficiency grade dropped from IE3 to IE1. Spectrum analysis by Tesla’s laboratory revealed that this anomaly caused the peak electromagnetic interference to exceed the 150kHz frequency band by 18dBμV, triggering a protective power-off by the on-board BMS. Delphi successfully controlled the iron loss at 3.2W/kg by optimizing the lamination process of silicon steel sheets (burrs ≤0.005mm), which was 40% lower than the industry average.
The economic benefits of maintenance highlight the preventive value. Predictive maintenance systems (such as Siemens Sidestream) warn of faults by monitoring current volatility. Practical applications by North American freight companies have shown that replacing worn pump bodies two weeks in advance can avoid downtime losses of 8,500 per vehicle. Comparative data shows that for every 1A abnormal increase in current, the fuel system will consume an additional 38kWh of electricity annually. Calculated at a commercial electricity price of 0.18/kWh, the potential loss for a fleet of a thousand vehicles amounts to $6,840 per year.
Extreme cases verify the tolerance limit of the system. During the overpressure test of the fuel pump in an F1 racing car (designed pressure of 12bar/ measured pressure of 18bar), the current suddenly soared to 145A (conventional 30A), at which point the probability of ceramic bearing breakage was as high as 73%. The ECE R110 regulation of the European Motor Vehicle Commission stipulates that pumps used in LPG systems must pass a continuous 2-minute test with an overload current of 150% and maintain an insulation resistance of over 100MΩ. In the recall case of the Munich Technical Inspection Association in 2023, non-compliant products increased the risk of vehicle self-ignition by 400%.
The optimization strategy requires multi-layer protection. Mitsubishi Heavy Industries suggests: Using a 0.02mm precision laser alignment installation can control the current deviation within ±3%. Combined with an IP69K protection grade connector (with a insertion and extraction force of 60N±5N), the failure interval can be extended to 15,000 hours. The Volvo VDS4 standard requires a 25% increase in the cross-sectional area of the conductor (such as 2.5mm² cables for 12V/15A systems), which has reduced the wiring harness failure rate of the Chilean copper mine fleet by 89%.