Fuel Injector: Description and Operation

The fuel injectors are solenoid operated valves that are pulsed by the ECM. The mechanical design of the injectors incorporates a pintle valve with a waisted shape tip passing through the orifice at the bottom of the injector body. The waisted shape of the pintle tip and orifice cause the fuel flow to form a cone-shaped spray of small fuel particles. The fuel inlet at the top of the injector has a small filter to trap any debris that may be present in the fuel. "0" Rings are used to seal the injector between the fuel rail and intake manifold.

The electrical pulses applied to the injector coil by the ECM attract the head of the pintle to the coil armature. This action overcomes spring pressure and allows fuel to flow through the annulus between the pintle tip and the orifice. Full valve lift (approximately 0.006 in) is reached in about 1 millisecond. The resistance of the fuel injector coil is approximately 2.5 ohms.