Fuel Charging and Controls
The fuel charging and controls system consists of the following:
- Electronic throttle body
- Fuel injectors
- Fuel charging wiring harness
- Fuel rail
The fuel charging and controls system is:
- A sequential multiport fuel injection (SFI) system.
- Pulse-width modulated.
- Mass airflow controlled.
The powertrain control module (PCM) controls the fuel injection system. Injector pulse-width is varied to control the amount of fuel flow. Varying fuel pump output controls fuel pressure. The PCM commands the fuel pump driver module, which directly controls the fuel pump. The throttle body is electronically controlled by the engine management system (EMS). Throttle plate angle is changed electronically in response to throttle pedal movements initiated by the driver.
The fuel rail:
- Delivers fuel to the individual fuel injectors.
- Receives fuel from the fuel supply tube.
The electronic throttle body:
- Controls air supply to the intake manifold by electronically positioning the throttle plate.
- Is not adjustable.
- Must not be cleaned.
The fuel injectors:
- Are electronically operated by the powertrain control module (PCM).
- Atomize the fuel as the fuel is delivered.
- Each have an internal solenoid which opens a needle valve to inject fuel into the lower intake manifold.
- Are deposit-resistant.
The fuel pressure sensor:
- Maintains constant fuel pressure to the fuel injectors and throughout the fuel system.
- Is spring-loaded and operated by intake manifold vacuum.
The engine wiring harness:
- Connects the fuel injectors and other electronic engine controls, such as the throttle position (TP) sensor, to the PCM.
- Receives fuel injector signals from the PCM and transfers the signals to the fuel injectors.