FDS12 - Check Fuel Return System
^ Key Off.
^ Observe Service Precautions to avoid fuel spillage and injury.
^ Fuel return line disconnected at the fuel pressure regulator.
^ Check the fuel return system for restriction due to blockage, kinking, or pinching.
^ Disconnect the fuel return line near the fuel tank.
^ Apply 3-5 psi regulated shop air to the return line at the pressure regulator side.
^ Does air flow freely through the line?
YES -- Replace fuel pump assembly. Repeat Test Step FDS2 for verification. FDS2 - Fuel Pressure Test
NO -- Service the fuel return line. Reconnect fuel line. Repeat Test Step FDS2 for verification. FDS2 - Fuel Pressure Test