1979 Models

On 210 models, when engine speed exceeds a pre-determined RPM during deceleration, the carburetor anti-dieseling solenoid valve closes, shutting off fuel flow. See Figure. Whenever engine speed is below this pre-determined RPM, even during deceleration, the fuel shut-off system is inoperative. The system also does not operate when shift lever is in Neutral.

On Pickups, when intake manifold vacuum exceeds a pre-determined level deceleration, the fuel shut-off vacuum switch sends a signal to the anti-dieseling solenoid valve, shutting off fuel flow. See Figure. Whenever manifold vacuum is below this pre-determined level, the system is inoperative. The system is also controlled by the clutch switch and gear position switches (Neutral switch and inhibitor switch) so that system can be deactivated, even though vacuum is above the pre-determined level.