Fuel Injector
An electronically controlled valve that sprays a precise amount of pressurized fuel into the engine's intake manifold or combustion chambers.
A fuel injector is a small, electronically controlled solenoid valve that delivers fuel into the engine's cylinders. Under pressure from the fuel pump, the injector sprays fuel in a fine, atomized mist, allowing it to mix efficiently with incoming air for combustion. The engine control module (ECM) controls how long the injector stays open (pulse width) to maintain the optimal air-fuel ratio.
Modern engines use either port fuel injection (where fuel is sprayed into the intake port) or direct injection (where fuel is sprayed directly into the combustion chamber under extremely high pressure). Direct injection improves fuel efficiency and power but is more susceptible to carbon buildup on the valves.
Fuel injectors operate under harsh conditions and can become clogged by fuel deposits, carbon build-up, or microscopic debris passing through the fuel filter. A failing or dirty injector may leak, fail to open, or spray an uneven pattern. Symptoms of injector problems include engine misfires, a rough idle, engine hesitation, decreased fuel economy, a fuel odor, and diagnostic trouble codes indicating a lean or rich condition.
Professional injector cleaning services or replacement can restore engine performance, reduce emissions, and bring back lost fuel economy. Mechanics use specialized diagnostic equipment to test injector resistance, flow rate, and spray patterns.