Fuel Injector: Description and Operation

PURPOSE
The fuel injectors are electro-mechanical devices which meter and atomize fuel delivered to the engine.

OPERATION
An electrical signal from the Powertrain Control Module (PCM) activates the fuel injector allowing the fuel to flow. Since the fuel injector flow orifice is fixed and the fuel pump pressure drop across the injector tip is constant:

- fuel is atomized by the director plate at the point where the fuel separates

The injector is normally closed and is operated by 12 volt VPWR from the EEC power relay. The ground signal is controlled by the PCM.

CAUTION: Do not apply battery voltage directly to the injector electrical connector terminals. The solenoids may be damaged internally in a matter of seconds.

FEATURES
The fuel injector is a solenoid-operated valve that meters fuel flow to the engine. The injector is opened and closed a constant number of times per crankshaft revolution. The amount of fuel is controlled by the length of time the injector is held open.

- mounted in the lower intake manifold and positioned so that their tips are directing fuel just before the engine intake valve.

- fuel flow is regulated by the length of time the solenoid is energized.

- the injector is the Deposit Resistant (DRI) type and does not have to be cleaned. However it can be flow checked and if found outside of specification the injector should be replaced.