Deceleration Control System: Operation

When engine speed is above 800 RPM, vehicle speed is above 10 MPH, and clutch pedal is not depressed, vacuum through the TC solenoid valve is available to the diaphragm of the throttle closer. This retracts the throttle stop screw. The throttle closes completely.

A minimum amount of fuel required to keep engine running is drawn from the slow speed fuel system. When the throttle valve is closed, additional air is introduced to the intake manifold through the air valve. The control valve activates the air valve depending on the carburetor insulator vacuum level.