Deceleration Fuel Cut System: Operation

On all models except Tercel, slow speed circuit in carburetor operates except during prolonged periods of deceleration at high engine speeds. Under these conditions, computer turns off fuel cut solenoid valve and mixture is leaned out. This prevents overheating and afterburning in catalytic converter.

The Calif. Tercel secondary system and Federal Tercel system are operated only by a vacuum switch. There is no speed sensor or computer, and VCV (Fed. models only) is used for hose connection, not for vacuum control. Calif. primary system is same as those on all other models.