Deceleration Fuel Cut System: Operation

On all models except Tercel, the slow speed circuit in the carburetor operates except during prolonged periods of deceleration at high engine speeds. Under these conditions, the computer turns off the fuel cut solenoid valve and the mixture is leaned out. This prevents overheating and afterburning in the 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 (Federal models only) is used only for hose connection, not for vacuum control. The Calif. primary system is the same as those on all other models.