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Home >> Jeep >> 1981 >> Pickup J20, AWD >> Repair and Diagnosis >> Engine Performance >> Tune-Up >> Spark Control Systems >> Operation >> Reverse Delay Valve

Reverse Delay Valve

Some engines use this valve to improve cold driveability and reduce hydrocarbon emissions. The valve is installed in the vacuum line to delay the effects of manifold vacuum decrease which causes ignition timing to be retarded.