A fuel supply system is provided for delivering fuel from a tank to an engine of a motor vehicle through a fuel line. The system is provided with a pressure relief valve to divert fuel from the fuel line during engine shut down conditions when fuel flow to the engine is not desired. The pressure relief valve has a fuel outlet that is provided with backpressure during engine operation. The backpressure enables the pressure relief valve to be set at a lower level because the backpressure is added to set point pressure to determine opening of the pressure relief valve. Lowering the set point of the pressure relief valve allows fuel to be diverted from the engine at a lower fuel line pressure. In one embodiment backpressure is provided by fluid communication from a jet pump supplying fuel from the fuel tank to a fuel system reservoir.