Idle

When the engine is at operating temperature, this is a Closed Loop mode. At idle speed, the engine controller receives inputs from:

^ Air conditioning select signal (if equipped)

^ Air conditioning request signal (if equipped)

^ Battery voltage

^ Crankshaft position sensor

^ Coolant temperature sensor

^ Charge Air Temperature sensor

^ Manifold absolute pressure (MAP) sensor

^ Throttle position sensor (TPS)

^ Sync signal (in distributor)

^ Battery voltage

^ Neutral Safety Switch (Gear indicator signal)

^ Oxygen sensor

Based on these inputs, the following occurs:

^ Voltage is applied to the fuel injectors with the engine controller. This will control injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.

^ The engine controller monitors the O2 sensor input and adjusts air-fuel ratio by varying injector pulse width. It also adjusts engine idle speed through the automatic idle speed (AIS) motor.

^ The engine controller adjusts ignition timing by increasing and decreasing spark advance.

^ The engine controller operates the A/C compressor clutch through the clutch relay. This happens if A/C has been selected by the vehicle operator and requested by the A/C thermostat.