The Lincoln Navigator mixes fuel and air under pressure with a fuel injector. This function was previously performed passively by carburetors until the late 1980s. One advantage of fuel injectors is the programmable firmware that allows the fuel injector to handle different fuels. A fuel injector is comprised of only the nozzle and valve; it still requires the pump to pressurize the fuel.
Determine which fuel injector your Lincoln Navigator will need. This depends not only on the make and model, but also the engine size. Models built from 1998 to 2007 will have 5.4L Triton or InTech engine. Models made after 2007 only have the 5.4L Triton engine.
Detach the negative cable from the battery and relieve the fuel system pressure with a socket wrench. Remove the hoses for the air cleaner and brake booster vacuum. Unplug the electrical connector for the mass air flow sensor and the positive crankcase ventilation tube.
Disconnect the spring lock coupling for the fuel supply line with a socket wrench and detach the fuel injector electrical connectors. Remove the locking clips that keep the fuel injectors attached to the fuel rail.
Remove the fuel rail bolts and lift the fuel rail out of the engine compartment with the fuel injectors still attached. Discard the old O-ring seals.
Grease the new O-ring seals with clean engine oil before installation. Use a torque wrench to tighten the fuel rail bolts to 89 inch pounds.
Install the remaining components in the reverse order of removal.
