Deceleration

When the engine is at operating temperature, this is an Open Loop mode. During hard deceleration, the engine controller receives the following inputs:

^ Air conditioning select signal (if equipped)

^ Air conditioning request signal (if equipped)

^ Battery voltage

^ Coolant temperature sensor

^ Crankshaft position sensor

^ Charge Air Temperature sensor

^ Manifold absolute pressure (MAP) sensor

^ Throttle position sensor (TPS)

^ Sync signal (in distributor)

^ Neutral safety switch (gear indicator signal)

If the vehicle is under hard deceleration with the proper rpm and closed throttle conditions, the engine controller will ignore the oxygen sensor input signal. The controller will enter a fuel cut-off strategy in which it will not supply battery voltage to the injectors. If a hard deceleration does not exist, the engine controller will determine the proper injector pulse width and continue injection.

Based on the above inputs, the engine controller will adjust engine idle speed through the automatic idle speed (AIS) motor.

The engine controller adjusts ignition timing by turning the ground path to the coil on and off.

The engine controller opens the ground circuit to the A/C clutch relay to disengage the A/C compressor clutch. This is done until the vehicle is no longer under deceleration (if the A/C system is operating).