Air Injection: Testing and Inspection
Fig. 27 Air Injection System Schematic:
SYSTEM TEST:
1. Check and/or adjust the air pump drive belt. The injection air-filter must be checked or replaced (every 48,000 km / 30,000 miles) if necessary.
2. Blow low pressure air through all the connecting air hoses, the control vacuum hose and the air tube system to ensure open air passages.
Check hoses for aging and oil saturation, replace if necessary. Check electrical connection and wiring harness for vacuum solenoid valve.
When engine cold (less than 35° C / 95° F):
1. Disconnect the check valve from the air tube system leading to the exhaust ports.
2. IMPORTANT:
Complete step #3 within 60 seconds of starting engine.
Start engine.
3. At idle speed and partial load the injection air should exit below the check valve. This must last for approx. 60 seconds from engine start-up. After 60 seconds, the injection air must stop flowing through the check valve. If system performs differently, check all individual components as described below under INDIVIDUAL COMPONENT TESTS.
4. Reconnect the air tube and check valve.
When engine hot (more than 35° C / 95° F):
1. Disconnect the check valve from the air tube system leading to the catalytic converter. Remove the air hose routed to the intake-air cleaner housing from switching valve #2.
2. Start engine.
3. At idle speed and partial load the injection air should exit below the check valve. If not, check all individual components as described below under INDIVIDUAL COMPONENT TESTS.
4. Disconnect and plug the control vacuum hose at switching valve #2. The injection air should now exit at the air hose to the intake-air cleaner housing. If not, check all individual components as described below under INDIVIDUAL COMPONENT TESTS.
5. Turn engine off.
6. Reconnect all hoses and connections.
INDIVIDUAL COMPONENT TESTS:
NOTE: In order to operate correctly, the air injection system tubes and hoses must be in good condition, routed correctly and free of internal restriction.
AIR INJECTION AIR-FILTER
1. Check and/or replace the air-filter (recommended every 48,000 km / 30,000 miles). The filter is located in center front of engine between air intake ducts.
AIR PUMP AND DRIVE BELT
1. Check drive belt (recommended every 48,000 km / 30,000 miles) for tension and aging. Adjust or replace if necessary.
2. Disconnect air hose at air pump outlet.
3. Start engine.
4. A constant stream of air must exit the pump outlet. The higher the engine RPM, the stronger the air stream. If there is no air exiting the pump, replace with new pump and retest.
VACUUM SOLENOID VALVE
1. Check electrical connection and wiring harness for corrosion and defects.
2. Disconnect electrical connector at solenoid valve.
3. Disconnect vacuum line at switching valve #1. Blow through the vacuum line. Vacuum solenoid valve must be closed and block the air flow.
4. Apply 12 V positive battery power to one of the solenoid valve terminals. Ground the other terminal. Blow through the vacuum line. Vacuum solenoid valve should be open and air can flow to the throttle valve housing.
5. If valve fails the test, replace and retest with new valve.
6. Disconnect temporary power leads and reconnect vacuum hose and electric connector.
Fig. 5 Switching Valve:
SWITCHING VALVE #1 AND #2
1. Remove the switching valve from the engine.
2. Blow air through the valve. The valve should route the air from inlet (2) to outlet (4).
3. Connect a vacuum pump to the switching valve vacuum port (1) and apply vacuum.
4. The valve should route the air from inlet (2) to outlet (3).
5. If valve fails the test, replace and retest with new valve.
6. Reinstall switching valve.
CHECK VALVES
1. Remove the check valve from the engine.
2. Blow compressed air through the valve (in direction of system air-flow). The valve should be open.
3. Blow air through the valve against direction of system air-flow. The valve should close.
4. If valve fails the test, replace and retest with new valve.
5. Reinstall check valve.