EXHAUST EMISSION CONTROL SYSTEM Air Injection Valve (A.|.V.) System Description (Cont'd) AB. VALVE This valve is actuated by intake manifold vacuum to prevent after burning in the exhaust system at the initial period of deceleration. At this period, the mixture in the intake manifold becomes too rich to ignite and burn in the com- bustion chamber and burns easily in the exhaust system with injected air in the exhaust manifold. To intake manifold vacuum i e 7 e To Intake . 7 manifold . g A . From air cleaner E5069 Inspection PRELIMINARY INSPECTION Check hose for Iooseness, flatting, damage or faulty connections, and each part for proper installation. If necessary, replace. AIR INJECTION VALVE (A.|.V.) AND FILTER 1. Disconnect air injection hose at air injection pipe side. Suck or blow hose to make sure that air flows only on the air injection pipe side. 8 seczasn 2. Check air injection valve for binding or dam age. At the same time, check filter for damage or plugging. If necessary, replace. A.B. VALVE 1. Warm up engine thoroughly. 2. Disconnect hose from air cleaner, and place a finger near the outlet. 3. Run engine at about 3,000 rpm under no-load, then quickly return it to idling. If you feel a pull or suction force on your finger, the A.B. valve is functioning normally. If no suction is felt, replace the A.B. valve, Samson