Spark Control Systems: Description: Notes

American Motors uses 7 spark control devices to assist the ignition system in controlling exhaust emissions. They are the Spark Coolant Temperature Override (CTO) Switch, the Non-Linear Vacuum Regulator (NLVR) Valve, Forward and Reverse delay valves, a Vacuum Solenoid Valve (VSV) and a Thermal Vacuum Spark Control Valve used in conjunction with a Vacuum Spark Control Delay Valve (on 4 cylinder models).