Low-quality Fuel is one of the key causes behind the shorter lifespan of Fuel pumps. Studies suggest that gasoline with sulfur levels greater than 50ppm can increase the corrosion rate of metal components within the Pump by three times. For example, in India’s market in 2020, the average lifespan of Delphi’s HP series Fuel pumps dropped from 120,000 kilometers to 40,000 kilometers due to low-quality fuel. When the water content in the fuel is more than 0.15%, then the lubrication characteristic of the vane pump reduces by 40%, the friction factor rises from 0.08 to 0.25, thus leading to a 30% increase in the motor load current and a 60% reduction in the carbon brush wear cycle (normal life is 5000 hours vs.) 2000 hours in poor-quality oil. The U.S. Department of Energy show that when the impurity concentration in Fuel exceeds 5mg/L, the possibility of clogging of the oil inlet filter screen of the Fuel Pump is as high as 78%, and the pump body must operate at 120% of the rated power. The maximum temperature of the bearing is above 95°C (the design temperature is 80°C), and the failure rate increases by 4.2 times.
Voltage fluctuations directly threaten the stability of the Fuel Pump. In a single instance, since the Jeep Wrangler generator regulator malfunctioned, the output voltage rose to 16.8V from 13.5V, and therefore the temperature rise rate of the Bosch 044 pump motor winding was 8°C/minute, while the carbonization time of the insulation layer was reduced from 10 years to 11 months. Industry statistics show that if the deviation of supply voltage is more than ±10%, the armature current fluctuation range increases by 35%, commutator sparks increase 50 times a second, and the lifespan of the carbon brush decreases by 70%. Tesla’s 2022 Cybertruck recall revealed that the on-board power management system flaw exposed the Fuel Pump to 14.5V constant voltage (7.4% higher than the standard), reducing motor efficiency by 22% and increasing power consumption by 18% year-on-year.
Mechanical overload and design mismatch is also a key reason. After a change by Harley-Davidson user from the original factory flow rate of 28L/h to a flow rate of 45L/h, fuel pipeline pressure increased from 4bar to 6.5bar, plunger pump reciprocating frequency increased from 3000 times/minute to 4500 times/minute, and the wear rate of sealing ring doubled by 200%. Leakage followed after only 8,000 kilometers of usage. SAE research shows that when the pressure drop of the Fuel filter exceeds 0.7bar, the Fuel Pump will have to do an additional 15%-20% of work, and the axial thrust of the impeller will rise by 12N (the design value is 10N), which will suddenly reduce the service life of the thrust bearing from 80,000 kilometers to 23,000 kilometers. Ford disclosed in 2021 that the EcoBoost engine contained a defect of more than ±5% in the pressure sensor of the high-pressure Fuel rail, causing the Fuel Pump to operate for a longer time at a pressure of 105bar (nominal value 90bar), and the threefold increase in wear rate.
Failure to keep speed accelerates the wear of the Fuel Pump. Statistics show that in vehicles where the fuel filter element is not replaced at regular intervals (recommended interval 20,000 kilometers), the concentration of particulate matter at the inlet end of the pump body can be six times greater than in the clean state, raising the clearance between the rotor and pump casing from 0.03mm to 0.12mm (safety limit 0.05mm), and reducing the volumetric efficiency by 40%. For instance, by prolonging the replacement period for the filter element to 40,000 kilometers, a certain Didi fleet’s Fuel Pump replacement rate rose from the industry standard of 5% to 27%, and the average maintenance expenditure per vehicle per year increased by 1,800 yuan. BMW technical notice indicates that without the use of anticoagulant additives in a freezing temperature of -30°C, Fuel viscosity will increase by 30%, the starting torque of the Fuel Pump will be 50% above rated value, and the risk of motor clogging will increase by 18%. These occurrences account for 41% of fault repair reports for winter in the Arctic.
The deficiencies in the production craftsmanship of the manufacturer also cannot be ignored. In Continental’s recall lots in 2023, because the thickness of the electroplating layer is less than 8μm (the design requirement is 12μm), the corrosion depth of the Fuel Pump gear shaft in the salt spray test is as much as 0.15mm/ year (acceptable value < 0.05mm/ year), and the rate of early occurrence of faults reached up to 63%. Toyota’s hybrid car had in the past resulted in 0.2mm microcracks due to a ±5°C temperature difference in the molding temperature of the resin pump housing. The fuel permeability was three times greater than the European standard EC79/2009, and the leakage rate per 100,000 kilometers grew from 1% to 22%. Scanning electron microscopy study at a third-party laboratory shows that lower-grade copper alloy brushes with below 85% copper content increase the Fuel Pump’s contact resistance by as much as 0.8Ω, cause a local temperature rise of over 120°C, and double the brush length wear from 12mm to 3mm (failure is at 5mm).