Reverse Delay Valve

PURPOSE
This valve, used in conjunction with the forward delay valve, functions to improve cold engine driveability and reduce hydrocarbon emission.

OPERATION
When the engine is started, manifold vacuum applied to the distributor advance mechanism advances ignition timing. During acceleration, manifold vacuum decreases and ignition timing is retarded. The one-way reverse delay valve delays the effects of the decrease in manifold vacuum, thereby preventing the sudden retarding of ignition timing during acceleration.