Fuel Injectors
The port fuel injector solenoid is controlled by the ECM. The injector consists of a valve body with a specially ground needle valve. The moveable armature is attached to the needle valve. Needle valve is held against nozzle sealing seat by spring pressure.
Each injector utilizes a double-wire connector. One wire supplies voltage when ignition is on. Second wire connects to the internally regulated ECM ground and controls injector pulse width. Electric pulses (generated by the ECM) produce a magnetic field in injector solenoid winding. This draws the armature back against spring pressure and lifts needle from the seat, allowing pressurized fuel to be injected. When injector is de-energized, spring pressure forces the needle valve closed. See Fig 1 .
Fuel injector is installed in intake manifold at each cylinder. Injector sealing is provided by "O" rings. Lower "O" ring seals between injector and intake manifold. Upper "O" ring seals between injector and fuel rail. Always replace "O" rings when injector is removed.