The low-pressure filter between the supply tanks and the engine serves to protect which components?

• A. The engine-driven fuel pump and various control devices
• B. The injectors
• C. The exhaust system
• D. The crankcase

Answer: (A)

Fuel filtration on the low-pressure side protects the components that actually move and control the fuel flow. Placing a filter between the supply tanks and the engine-driven pump keeps dirt, rust, and other contaminants from entering the pump and the fuel-control devices. If debris reaches the pump, it can cause wear, cavitation, or sticking of metering valves, leading to erratic fuel metering or pump failure. Once fuel passes the pump, the high-pressure side handles the injectors and their own filtration, but this low-pressure filter specifically shields the pump and control circuitry from damage and improper operation. The exhaust system and crankcase aren’t part of the fuel system, so they aren’t protected by this filter.