Description & Operation

Spark Delay Valves (SDV) are installed on many engines to permit closer control of vacuum operated emission related equipment. All Spark Delay Valves have an internal sintered orifice to slow air flow in one direction, a check valve to allow free air flow in the opposite direction, and a filter.

Fig 1: Cutaway View of Spark Delay Valve

Courtesy of FORD MOTOR CO.

Fig 2: Spark Delay Valve Schematic

Courtesy of FORD MOTOR CO.