Air Injection: Testing and Inspection

1. Disconnect and plug air suction hose from air control valve B.
2. Remove air cleaner cover and filter.
3. Start engine and check for bubbling noise from air suction port at idle. Bubbling noise should be heard.
4. If bubbling noise is heard, proceed to step 12. If bubbling noise is not heard, disconnect hose No. 5 from air suction cut-off diaphragm and check for vacuum.
5. If vacuum is present, replace air suction cut-off diaphragm and repeat test. If vacuum is not present, reconnect No. 5 hose and proceed to step 6.
6. Disconnect hose No. 15 which is routed from control box at vacuum hose manifold, then check for vacuum at vacuum hose manifold. Vacuum should be present.
7. If vacuum is not present, check vacuum line No. 15. If vacuum line is clear, replace air bleed valve A and repeat test. If vacuum is present, check for voltage at control box white/red wire of vacuum switch C.
8. If voltage is not present, check wiring and fuse. Repair or replace as required, and repeat test. If voltage is present, proceed to step 9.
9. Remove control box from firewall, then the control box cover.
10. Check for continuity between vacuum switch wire terminals with engine idling. Continuity should be present.
11. If continuity is present, replace air suction control solenoid and repeat test. If continuity is not present, replace vacuum switch and repeat test.
12. Heat air bleed valve A to approximately 140°F with suitable hot air gun. Check that bubbling noise stops.
13. If bubbling noise stops, proceed to step 14. If bubbling noise does not stop, replace air bleed valve A and proceed to step 14.
14. Allow air bleed valve to cool, then disconnect hose No. 20 routed from control box at vacuum hose manifold and connect suitable vacuum pump to hose.
15. Apply 1.18 inches Hg vacuum or higher while engine is idling, then check for bubbling noise. Bubbling noise should stop.
16. If bubbling noise stops, test is complete. If bubbling noise is heard, disconnect hose No. 5 from air suction cut-off diaphragm and check for vacuum.
17. If vacuum is not present, replace air suction cut-off diaphragm and repeat test. If vacuum is present, proceed to step 18.
18. Check continuity between vacuum switch wire terminals with vacuum applied to vacuum switch. Continuity should not be present.
19. If continuity is not present, replace air suction control solenoid valve and repeat test. If continuity is present, replace vacuum switch and repeat test.