System Testing
- Disconnect and plug air suction hose from air control valve B. Remove air cleaner cover and filter. Start engine and let idle. Check for bubbling noise from air suction port. See Fig 2 .
- If bubbling noise is heard, proceed to step 7). If bubbling noise is not heard, disconnect hose number 5 from air suction cut-off diaphragm and check for vacuum.
- If vacuum is present, replace air suction cut-off diaphragm and retest. If no vacuum is present, reconnect hose disconnected in step 2).
- Disconnect hose number 15 from control box at the vacuum hose manifold. Check for vacuum at vacuum hose manifold. If no vacuum is present, check vacuum hose. If okay, replace the air bleed valve A and retest.
- If vacuum is present, check for voltage at vacuum switch B (Black/Yellow wire) in control box. If no voltage, check and repair wiring or fuse.
- Remove control box cover. Check for continuity at vacuum switch B terminals with engine at idle speed. See Fig 1 . If continuity is present, replace air suction control solenoid valve and retest. If no continuity, replace vacuum switch B and retest.
- Heat air bleed valve to 140°F (60°C). Ensure bubbling noise stops. If not, replace air bleed valve. Allow air bleed valve to cool before proceeding.
- Disconnect hose number 7 from control box at vacuum hose manifold and connect a vacuum pump to hose. With engine at idle speed, apply 1.5 in. Hg. If bubbling noise stops, system is okay.
- If bubbling noise is heard, disconnect hose number 5 from air suction cut-off diaphragm and check for vacuum. If no vacuum is present, replace air suction cut-off diaphragm and retest.
- Apply vacuum to hose number 7 of vacuum switch B. Check for continuity at terminals of vacuum switch B. If continuity is present, replace vacuum switch B and retest. If no continuity is present, replace air suction control solenoid valve and retest