Fuel Injector: Description and Operation

The Model 220 unit consists of three assemblies:

- Fuel Meter Cover
- Fuel pressure regulator
- Fuel Meter Body
- Fuel injectors
- Throttle Body
- Two throttle valves to control air flow into the engine.
- Idle Air Control (IAC) valve
- IAC air passage splitter for improved distribution of idle air flow
- Throttle Position (TP) Sensor
- Vacuum ports located at, above, or below the throttle valves to generate vacuum signals to various controls and accessories.

Fuel Injectors
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 TB 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.