Spark Control Systems: Description: Notes

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