Injector FAQ

FAQ: How Does a fuel injector work?

ERIKC Answer: Fuel under pressure is sprayed in a very fine mist from the tip of the injector. To achieve this, a current must flow through the injector. Contrary to popular belief, this is NOT done by sending power to the injector. Fuel injectors are normally fed power whenever the ignition key is on, but the circuit is not completed and therefore the injector is still closed. The computer controls the ground side, of the circuit. When the computer provides the ERIKC injector with a ground, the circuit is completed and current is allowed to flow through the injector. This energizes an electromagnetic coil inside the injector, which pulls a sealing mechanism such as a pintle, ball, or disc away from its seat. This makes it possible for fuel to flow through the injector and into the engine. When the computer removes the electrical ground to the injector, the electromagnetic coil becomes demagnetized and a spring forces the pintle, ball, or disc shut to cut off fuel flow.

FAQ: What is Injector Duty Cycle?

ERIKC Answer: To control the amount of fuel that enters the engine the injectors are turned on and off or pulsed very quickly. The amount of time an injector is turned on to deliver fuel is known as the duty cycle. This is measured as a percent, so 50% duty cycle indicates that the injector is held open and held closed for an equal amount of time. When the engine needs more fuel, the time that the injector stays on (its duty cycle) increases so that more fuel can flow into the engine. If an injector stays on all the time, it is said to be static (wide open, or 100% duty cycle).