What are the symptoms of a faulty high-pressure fuel pump in a diesel vehicle?

[JasonRose]

High-pressure fuel pump failure conditions: 1. False overspeeding refers to when the diesel engine starts with normal idle speed, but does not decelerate after accelerating and releasing the throttle. This occurs when the injector plunger is worn out, and the fuel rack is set at the idle position for idle fuel supply. Once the throttle is increased to accelerate, and then released, the fuel rack can return to the idle position, but the governor's moving parts and transmission components are stuck in the high-speed position due to excessive wear, preventing the speed from decreasing. If this phenomenon occurs, the fuel injection pump must be inspected and repaired. 2. No fuel comes out of the high-pressure fuel line, but there is fuel in the low-pressure fuel circuit, and the diesel engine cannot start, indicating that the fuel supply rack is stuck in the non-supply position. In this case, the fuel injection pump also needs immediate inspection and repair. 3. The speed fluctuates up and down, which is a sign that the fuel supply rack is not flexible or the internal components of the governor are excessively worn, leading to increased clearance. Therefore, the fuel injection pump also needs to be inspected and repaired.