What does it mean when the actual rail pressure is severely low?

[DiChristian]

Actual rail pressure being severely low indicates insufficient fuel in the fuel rail. Below are relevant explanations: 1. Fuel system issues: In northern regions, the failure rate of fuel systems is quite high, such as: filter clogging, poor-quality diesel being refueled, wax deposition causing insufficient supply in the low-pressure fuel circuit. Additionally, leaks in the high-pressure section, such as loose high-pressure fuel pipe connections causing leaks, or excessive injector return flow, all belong to high-pressure leaks. 2. Insufficient fuel pressure: The vehicle starts normally under regular conditions and runs without issues, but fails to start after shutting down. The ignition point of starting fluid is relatively low, allowing the engine to fire. Wear of the fuel transfer pump and plunger can result in the fuel intake pressure not meeting requirements during startup. If the overpressure protection valve and bypass valve are stuck, they can also cause this fault problem.