Fuel Injection Operation

The fuel injector, when turned on by the ECM, atomizes and directs fuel into the intake manifold. Fuel Injectors

There is one injector per cylinder mounted in the intake manifold before the intake valve(s). The injectors are installed with an insulator/seal on the manifold end to insulate the injector from heat and prevent atmospheric pressure from leaking into the manifold. The fuel delivery pipe secures the injector. An O-ring between the delivery pipe and injector prevents the fuel from leaking.

Different engines require different injectors. Injectors are designed to pass a specified amount of fuel when opened. In addition, the number of holes at the tip of the injector varies with engines and model years. When replacing an injector it is critical that the correct injector be used.

Inside the injector is a solenoid and needle valve. The fuel injector circuit is a ground switched circuit, To turn on the injector, the ECM turns on a transistor completing a path to ground. The magnetic field pulls the needle valve up overcoming spring pressure and fuel now flows out of the injector. When the ECM turns off the circuit, spring pressure will force the needle valve onto its seat, shutting off fuel flow.

Inside the injector is a solenoid and needle valve. The fuel injector circuit is a ground switched circuit, To turn on the injector, the ECM turns on a transistor completing a path to ground. The magnetic field pulls the needle valve up overcoming spring pressure and fuel now flows out of the injector. When the ECM turns off the circuit, spring pressure will force the needle valve onto its seat, shutting off fuel flow.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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