Fuel Injector: Description and Operation

A fuel injector is a solenoid-operated device controlled by the ECM. When the ECM energizes the solenoid, a normally closed ball valve is lifted off its seat.
Pressurized fuel is injected in a conical spray pattern against the walls of the throttle bore above the throttle valve. Excess fuel, which is not needed by the injector, passes through the pressure regulator before being returned to the fuel tank. The throttle body features two injectors designed with the flow capacity required for the engine.
A fuel injector which does not open may cause a no-start condition. An injector which is stuck partly open will cause a long crank time. Also, dieseling could occur because some fuel would be delivered to the engine after the key is turned "OFF". An injector stuck completely open will cause a stall or no-start condition.