Vacuum Restrictor: Description and Operation

Vacuum Restrictor:

The vacuum restrictor may be inserted into the vacuum hose line or act as the joint between two vacuum hoses. This orifice-type restrictor controls the vacuum flow rate and/or timing in action of a vacuum operated component. The vacuum restrictor is commonly used in controlling the timing of the EGR valve opening and closing, the rate at which fuel vapors are absorbed by the charcoal canister, and ignition spark timing advance while the vehicle is at part throttle.