F 150 2WD Pickup V8-5.4L SOHC VIN 5 (2004)
Fuel Injector: Description and Operation
Natural Gas Fuel System
FUEL INJECTOR(S)
Fuel Injector
The fuel injector (Figure 81) is a solenoid-operated valve that meters fuel flow to the engine. The fuel injector is opened and closed every other
crankshaft revolution. The amount of fuel is controlled by the length of time the fuel injector is held open.
The fuel injector is normally closed and is operated by 12 volt VPWR from the power relay. The ground signal is controlled by the PCM.
The fuel injectors are used to meter natural gas to each combustion cylinder. Although the natural gas fuel injectors appear very similar to some gasoline
fuel injectors, they are unique. Flow capacity of these fuel injectors is 6 to 12 times as large as various gasoline fuel injectors. Electrical resistance is
much lower than typical gasoline fuel injectors (4.6 ohms as opposed to 14.5 ohms). To accommodate this lower resistance, a fuel injector driver
module is used to convert the PCM fuel injector driver signal to the signal required by the fuel injector.
