Air Injection: Testing and Inspection

Fig. 98 Check Air Switching Valve With Engine Cold:

Fig. 1 Vacuum Transmitter Valve Test:

Fig. 1 Vacuun Switching Valve Test:

1. Visually inspect air injection hoses, fittings and components for damage and wear, and repair as needed.
2. Inspect wiring and electrical connectors to sensors control valve and computer, and repair as needed.
3. Ensure engine is cold (coolant temperature below 43°F), then disconnect air bypass hose from air cleaner, Fig. 98
4. Start engine and observe air flow from bypass hose. Air should be continuously discharged from hose.
5. Warm engine to 64 - 109°F while observing air flow from bypass hose. With coolant temperature in specified range, no air should be discharged from hose.
6. Warm engine to normal operating temperature and observe air flow from bypass hose. With engine at idle, no air should be discharged from hose.
7. Run engine at 3000 RPM while observing air flow from bypass hose. Air should be discharged from hose intermittently.
8. Momentarily race engine, then release throttle linkage. Air should be discharged from bypass hose for 1 - 3 seconds after throttle is released.
9. Check the Vacuum Transmitter Valve (VTV), disconnect the hose between the VTV and gas filter at the VTV side. Check that air is discharged from the air by-pass hose within 7 - 14 seconds, Fig. 99
10. Check the Vacuum switching valve (VSV), disconnect the hose between the VSV and ASV at the VSV side. Connect a vacuum guage to the VSV port, Fig. 100 Increase the engine speed to 4,800 rpm and check that the vacuum gauge indicates zero.
11. Pinch the hose between the vacuum switch and air pipe. Increase the engine speed to 4,800 rpm and check that the vacuum gauge indicates manifold vacuum. Disconnect vacuum guage and reconnect VSV hose.
12. If system fails to perform as outlined, test components individually.