Other Control Functions

General System Description:

STARTING CONTROL
When the engine is started, the Engine Control Module (ECM) provides a rich mixture by increasing fuel injector duration.

FUEL PUMP CONTROL
^ When the ignition switch is initially turned on, the ECM supplies ground to the main relay which supplies current to the fuel pump for two seconds to pressurize the fuel system.

^ When the engine running, the ECM supplies ground to the main relay which supplies current to the fuel pump.

^ When the engine is not running and the ignition is on, the ECM cuts ground to the main relay which cuts current to the fuel pump.

FUEL CUT-OFF CONTROL
^ During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at speeds over 1,100 rpm.
^ Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm (F22B1 engine), 6,600 rpm (F22B2 engine) regardless of the position of the throttle valve to protect the engine from over-running.

A/C COMPRESSOR CLUTCH RELAY
When the ECM receives a demand for cooling from the air conditioning system (compressor control unit), it delays the compressor from being energized, and enriches the fuel mixture to assure smooth transition to the A/C mode.

EVAPORATIVE EMISSION (EVAP) PURGE CONTROL SOLENOID VALVE
When the engine coolant temperature is below 167°F (75°C), the ECM controls the EVAP purge control solenoid valve which cuts vacuum to the EVAP purge control canister.

INTAKE AIR RESONATOR (IAR) CONTROL SOLENOID VALVE (VTEC only)
When the engine rpm is below 2,900 rpm, the IAR control solenoid valve is deactivated by the ECM, and intake air does not flow from the IAR. At engine speeds between 2,900 rpm and 3,700 rpm (mid-range), the solenoid valve is activated by a signal from the ECM, and intake air flows from the IAR.

FUEL INJECTION AIR (FIA) CONTROL SOLENOID VALVE (VTEC only)
When the engine speed is between 1,300 rpm and 4,500 rpm, the ECM supplies ground to the FIA control solenoid valve, sending intake air to the fuel injectors.

EXHAUST GAS RECIRCULATION (EGR) CONTROL SOLENOID VALVE
When the EGR is required for control of oxides of nitrogen (NOx) emissions, the ECM controls the EGR control solenoid valve which supplies regulated vacuum to EGR valve.

ALTERNATOR CONTROL
The system controls the voltage generated at the alternator in accordance with the electrical load and driving mode, which reduces the engine load to improve the fuel economy.