General Information
GENERAL DESCRIPTIONThe Multiport Fuel Injection System consists of sensors, actuators and the engine control module (ECM)
The ECM (or PCM) carries out activities such as fuel injection control, idle air control, and ignition timing control. In addition, the ECM (or PCM) has several diagnostic test modes which simplify troubleshooting when a problem develops.
In addition, the ECM (or PCM) is equipped with several diagnostic test modes which simplify troubleshooting when a problem develops.
FUEL INJECTION CONTROL
The ECM (or PCM) controls injector drive times and injector timing to supply the optimum air/fuel mixture to the engine according to the continually-changing engine operation conditions. A single injector is mounted at the intake port of each cylinder. The fuel pump supplies pressurized fuel from the fuel tank to the fuel injectors. The fuel pressure regulator controls the fuel pressure. Thus, the regulated fuel is distributed to each injector.
Fuel is normally injected for each cylinder every two rotations of the crankshaft. The firing order is 1-3-4-2. Each cylinder has a dedicated fuel injector. This is called "multiport." The ECM (or PCM) provides a richer air/fuel mixture by carrying out "open-circuit" control when the engine is cold or running under high load conditions. Thus, engine performance is maintained.
In addition, when the engine is under normal operating temperature after warming-up, the ECM (or PCM) controls the air/fuel mixture according to the heated oxygen sensor signal. This control is a "closed-loop" control. The closed-loop control achieves the theoretical air/fuel mixture ratio where the catalytic converter can obtain the maximum cleaning performance.
IDLE AIR CONTROL
The engine control module controls the amount of air that bypasses the throttle valve according to changes in idling conditions and engine load during idling. Thus, idle speed is kept at an optimum speed.
The ECM (or PCM) drives the idle air control (IAC) motor according to engine coolant temperature, A/C, and other electrical load. Thus, idle speed is kept at an optimum speed. In addition, when the air conditioning switch is turned off and on while the engine is idling, the IAC motor adjusts the throttle valve bypass air amount. Thus, idle speed is maintained at constant speed regardless of various engine load conditions.