Pulsed Secondary Air Injection: Testing and Inspection

Fig. 47 Testing the secondary air supply system:

Fig. 48 Testing the secondary air supply system (Federal):

1. Disconnect the air supply hose form the air cleaner and check for vacuum by placing your thumb over the end of the air supply hose, Fig. 47 (or Fig. 48 for Federal vehicles only). CAUTION! When suction is felt during this procedure use care not to be burned by exhaust gas flowing backward due to a broken reed valve.
2. Verify that when the engine is cold (coolant temperature less than 63 degrees C or 145 degrees F) suction is present at idle.
3. Allow the engine to warm up (coolant temperature greater than 63 degrees C or 145 degrees F) and verify that when the engine is initially started warm, suction is present for the first 70 seconds after start and then suction stops.
4. Accelerate the engine to 4,000 rpm and then allow it to quickly decelerate. Verify that vacuum is present during deceleration.