The oil pressure data being lower than the critical value is the core evidence: The pressure of the Fuel rail is measured using a mechanical oil pressure gauge. If the pressure value of the EFI system at idle speed is lower than 35 psi (such as the standard value of 44±5 psi for Toyota Camry), or it cannot maintain 45 psi under a load of 3000 rpm (fluctuation >5%), it indicates that the flow supply of the Fuel Pump is insufficient. The 2023 SAE study shows that when analyzing a sample of 500 faulty vehicles, the probability of acceleration lag increases to 78% when the median pressure drops by 12%, and the median repair cost reaches $450. A typical case is the recall of Ford F-150 in 2022 (Announcement 22S17). Due to the fatigue of the fuel pump impeller, the pressure dropped to 28 psi, causing the rate of stalling accidents to increase threefold.
Abnormal parameters of the power system are associated with decreased pump efficiency: When the OBD-II detects fault code P0087 (low fuel pressure), if the standard deviation of the air-fuel ratio fluctuation is greater than 0.3 (normal value <0.1), and the torque output attenuation rate in the high-speed zone (>4000 rpm) is greater than 15%, it can be determined that the performance of the pump body has declined. Volkswagen Group’s technical Bulletin TPI 2053368 states that when the load current of the oil pump rises to 12A (the standard value is 8A±0.5A), the flow output will decrease by 20% and the fuel consumption per 100 kilometers will increase by 1.8 liters. In the actual road test, before the fuel pump failure of a certain 2018 Honda CR-V, the 0-100km/h acceleration time was extended from 9.2 seconds to 11.5 seconds.
Abnormal noise and abnormal working cycle reveal mechanical defects: The normal noise value of high-performance fuel pumps is less than 45 decibels (measured at a distance of 50cm). When high-frequency whistling with an amplitude greater than 0.5mm (frequency >4000Hz) occurs, it often indicates wear of the motor bearings. According to the Bosch maintenance manual, if the pump body operates continuously for more than 10 seconds during the cold start stage (the standard is 3 to 5 seconds), or the start-stop frequency per hour is greater than 120 times (the designed value is ≤60 times), then 70% of the wear life has been consumed. According to the statistics of the European Automobile Club (ACE) in 2021, the average period for such signs to develop into complete failure is only 1,800 kilometers.
Thermodynamic parameters reveal efficiency deterioration: Infrared thermal imaging shows that the surface temperature of the abnormal fuel pump can reach 95°C (safety upper limit 80°C), while the fuel temperature rises to 60°C (standard <45°C). Lexus’s technical report confirmed that when the temperature difference at the fuel pump outlet is greater than 8°C, the change in gasoline density causes the injection error rate to rise to ±7% (±2% for qualified products). This phenomenon is associated with the 2023 North American NHTSA recall case 23V-085: The Hyundai Sonata has a 22% increased risk of low-speed collision due to poor heat dissipation of the fuel pump, causing a deviation in the concentration of the oil-gas mixture.
The intelligent diagnostic tool provides precise failure prediction: when the ripple coefficient detected by the current sensor at the front end is greater than 10% (the standard for new pumps is less than 3%), combined with the regression analysis of the pressure sensor data (R²>0.85), it can issue a warning 400 hours in advance. Audi DEKRA certification data indicates that such predictions have reduced replacement costs by 55% and avoided a 92% decrease in the rate of breakdowns. The AI diagnostic cloud platform launched by Mercedes-Benz in 2024, by comparing the operating parameters of Fuel pumps of 150,000 vehicles worldwide, has improved the fault location accuracy to 98%, significantly optimizing the maintenance and repair benefits.