What are the faults of a high-pressure fuel pump?
2 Answers
High-pressure fuel pump faults include the following points: 1. Abnormal instantaneous fuel pressure at idle when in neutral without air conditioning, caused by side leakage of the fuel pump and insufficient fuel supply pressure. Generally, normal idle fuel pressure may be below 0.7, but abnormal instantaneous fuel pressure is not constant; it is transient and requires careful observation. 2. Jerking when releasing the throttle, especially at speeds of 80 or 70. If releasing the throttle causes noticeable vehicle jerking and significant engine vibration, pull over and check the idle instantaneous fuel pressure. If it is low, the high-pressure fuel pump may be aging. The reason is that after releasing the throttle, the fuel supply suddenly decreases. Due to insufficient fuel supply pressure, the engine experiences inadequate fuel injection, causing a sudden drop in RPM. The engine's RPM cannot support the transmission's RPM, leading to vehicle jerking and engine shaking. 3. Difficulty starting when the engine is hot, while cold starts are fine. This is because the fuel pump is connected to the crankcase. If the fuel pump ages and leaks, gasoline can seep into the crankcase. Under the influence of oil temperature, this causes an overly rich air-fuel mixture in the cylinders, making it difficult to start.
A faulty high-pressure fuel pump can indeed be a headache. The most common issues are internal component wear, such as aging plungers or springs causing fuel pressure drops or fluctuations, leading to engine shaking and starting difficulties; damaged or aged seals can cause fuel leaks, not only wasting gasoline but also posing safety hazards; clogged filter screens from impurities result in insufficient supply, causing jerking and lack of power during acceleration; and electrical faults, such as sensor failures or corroded wiring connections leading to signal disruptions and inaccurate computer control. If you suspect a problem, it's best to test with a fuel pressure gauge. If the pressure is too low or fluctuates significantly, disassembly, cleaning, or replacement of related parts is necessary. Otherwise, prolonged neglect may damage the fuel injectors or even the entire engine system. As someone who frequently repairs cars, I recommend regular checks of fuel quality and filters.
