Fuel Charging and Controls

The fuel charging and controls system consists of the:
^ throttle body
^ fuel injectors
^ fuel charging wiring
^ fuel supply manifold
^ fuel pressure relief (Schrader) valve

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. At low speeds, the Idle Air Control (IAC) valve controls the bypass air around the throttle plate.







The fuel supply manifold:
^ delivers fuel to the individual fuel injectors.
^ receives fuel from the fuel supply line.







The throttle body:
^ controls air supply to the upper intake manifold by positioning the throttle plate.
^ connects the accelerator cable and the speed control actuator cable to the throttle plate.
^ is not adjustable.
^ must not be cleaned.
^ has a different linkage ratio depending on the type of transmission (automatic or manual).







The fuel injectors:
^ use new O-ring seals.
^ are electrically operated by the powertrain control module (PCM).
^ each have an internal solenoid that opens a needle valve to inject fuel into the lower intake manifold.
^ atomize the fuel as the fuel is delivered.
^ are deposit-resistant.
- Do not clean the fuel injectors.

The fuel pressure relief valve:
^ is used as a test port and to relieve fuel pressure.







The fuel charging wiring:
^ connects the fuel injectors and fuel pressure sensor to the engine wiring harness and the powertrain control module.
- Connectors on the right side fuel injectors are gray.
- Connectors on the left side fuel injectors are black.
^ receives signals from the powertrain control module and transfers the signals to the fuel injectors.