Fuel Pressure Relief Valve
WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.
- The left bank fuel rail contains a fuel rail pressure relief valve. The fuel rail pressure relief valve is controlled by a Pulse Width Modulation (PWM) signal from the ECM. Using the fuel rail pressure relief valve to regulate the fuel pressure in the high pressure system is one of the controls the ECM uses to regulate fuel delivered (injected) into the engine. Bled off fuel from the fuel rail pressure relief valve is routed to the return manifold in the bottom of the stage 2 fuel filter. When the engine shuts down and the ignition switch is turned OFF, the fuel pressure relief valve will open, allowing the fuel pressure inside the rails to depressurize. Before opening any high pressure components, make sure to wait a minimum of 10 minutes for fuel pressure and temperature to decrease.