What are the causes of abnormal rail pressure?

[VonChristopher]

Abnormal rail pressure may occur due to the following reasons: Faulty pressure switch: The engine utilizes a high-pressure common rail injection system to control fuel supply, where multiple cylinder injectors are fed by a single high-pressure fuel rail. If the fuel in the rail becomes insufficient due to pressure-related issues, it reduces the engine's power output per unit time, leading to abnormal rail pressure. Clogged oil passage: As engine oil passes through the fine pores of the oil filter, solid particles and viscous substances are trapped in the filter. A clogged filter prevents smooth oil flow, potentially rupturing the filter element or activating the safety valve, allowing unfiltered oil to bypass through the relief valve and carry contaminants back to lubrication points. Airborne pollutants may accumulate around the PCV valve, potentially causing blockage. A clogged PCV valve can cause contaminated gases to flow backward into the air cleaner, polluting the filter element and reducing filtration efficiency. This results in dirtier air-fuel mixture intake, further contaminating the crankcase, increasing fuel consumption, and causing abnormal rail pressure.