Which device relieves excess fuel pressure in the fuel system?

• A. Pressure regulator
• B. Check valve
• C. Overflow valve
• D. Fuel pump relief valve

Answer: (D)

Relieving excess fuel pressure is done by a valve that opens when the pump tries to push more fuel than the system can handle, sending the surplus back to the tank or pump suction. This pump relief valve is built into the fuel pump and acts automatically to prevent overpressure in the discharge path, protecting the pump, lines, and injectors from damage. While a regulator also helps control pressure, its primary role is to maintain the desired system pressure by routing extra fuel back, not to provide the dedicated relief path at the pump itself. The other components don’t serve this relief function—check valves prevent reverse flow, and overflow valves aren’t standard in this context. Therefore, the fuel pump relief valve is the device that relieves excess fuel pressure.