Ignition Retard System (6 Cyl. Models)

Disconnect vacuum advance hose from distributor and increase engine speed to 2500 ± 50 RPM. Check for vacuum at hose. If vacuum is present, system is operating correctly. If no vacuum is present, remove plug from two way valve and connect. voltmeter. Start engine and increase speed. Reading must be 12 volts below 2200 ± 100 RPM. If reading is 0 volts, replace speed relay. If voltage reading was correct, but system still is malfunctioning, replace two way valve.