Control Valve Test

Remove air cleaner, and hose from top of control valve. Start engine and run at idle speed. Pull off hose that goes to manifold vacuum. Look at white valve in control valve housing and wait five seconds, put manifold vacuum line back on valve. White valve should move upward for one to three seconds and then drop down. If white valve stays up for more than five seconds before dropping down, or will not move at all, it indicates a defective valve.