Computers and Control Systems: Description and Operation

Fig. 429 - Fuel Shut-Off System:

This system--Fig. 429--shuts off fuel supply during deceleration to reduce fuel consumption and help prevent a temperature rise in the catalytic converter during long periods of deceleration.

When manifold vacuum increases above a predetermined value during deceleration, the vacuum switch sends a signal to the anti-dieseling solenoid valve which shuts off fuel supply. When manifold vacuum drops below the predetermined value, this system is deactivated. This system is also controlled by the clutch switch, neutral switch, and inhibitor switch so that fuel is not cut off during certain conditions even if manifold vacuum is high enough to operate system.