How Fuel Injector Works

A fuel injector is an electronically controlled valve that both meters flow of fuel and atomizes fuel. The injector is located on the intake manifold of the engine, and is sealed between the manifold and the fuel supply rail.

Fuel injectors are normally fed power continuously when the ignition key is on. The computer controls the negative or ground side of the circuit. The (ECM or ECU or PCM) computer gathers information from various sensors and using this information, the computer determines the injector’s opening duration required for that combustion stroke. When the computer provides the injector with a ground (flips the switch on), the circuit is completed and current is allowed to flow through the injector’s electromagnetic coil.

Most injectors use a 10 to 20 micron internal final filter screen. A small 25% restriction in the injector filter will cause the ECM to increase the injector’s on-time by 25% to make up for the restricted filter and the loss of fuel flow!

The injector will remain open anywhere between 1 to 20 milliseconds depending on the engine’s needs (as determined by the ECM). The current stops when the computer removes the electric ground to the injector, the electromagnetic coil becomes de-energized and a small coil spring pushes the valve needle to the pintle seat and cuts off fuel flow.

Most dirty and clogged fuel injectors respond well to our ultrasonic fuel injector cleaning service and are restored to a “like new” clean condition and performance.