Spark Control System: Description: Notes

Vehicles use spark control devices to assist ignition system in controlling exhaust emissions. They are Spark Control Temperature Override (CTO) valve, Non-Linear Vacuum Regulator (NLVR) valve, Forward Delay Valve, Reverse Delay Valve and on 4-cylinder and Federal V6 engines, Vacuum Spark Control Delay Valve. System application depends upon engine size, emissions category and vehicle model.