Air Control Valve

1981 22R Engine
1. Disconnect air hose from check valve and air by-pass hose from air cleaner.

2. Disconnect vacuum hose between air switching valve and vacuum pipe at valve, and disconnect vacuum hoses from air control valve, then plug hose ends.

Fig.77 - Testing Air Control Valve:

3. With engine idling, apply vacuum directly to air control valve chamber "B" and air switching valve chamber "A", Fig. 77. Compressed air should come out of bypass hose at idle.

Fig.78 - Testing Air Control Valve:

4. Release vacuum from air control valve chamber "B" and apply vacuum directly to chamber "A" of air switching and air control valves, Fig. 78. Compressed air should come out of air hose to check valve at idle.

Fig.79 -testing Air Control Valve:

5. Release vacuum from air switching valve chamber "A" and apply vacuum directly to air control valve chamber "A", Fig. 79. Compressed air should come out of air bypass hose at idle.

6. Connect suitable air pump tester to air hose to check valve.

7. Apply vacuum directly to chamber "A" of air switching and air control valves.

8. Close off tester orifice, then gradually in- crease engine speed and measure relief valve opening pressure. Opening pressure should be 5 to 6.4 psi.

9. Remove tester and reconnect air and vacuum hoses to proper locations.

1981-82 3A-C Engine
1. Disconnect exhaust manifold check valve air hose and air cleaner by-pass hose.

2. Disconnect vacuum hoses from air control valve and air switching valve.

Fig.80 - Testing Air Control Valve:

3. With engine idling, apply vacuum directly to air control valve chamber "A" and air switching valve, Fig. 80.

4. Disconnect then reconnect vacuum hose from air by-pass valve. Compressed air should be momentarily discharged from air by-pass hose.

Fig.81 - Testing Air Control Valve:

5. Release vacuum from air control valve chamber "A" and apply vacuum directly to air control valve chamber "B" and air switching valve, Fig. 81. Compressed air should be discharged from by-pass hose at idle.

Fig.82 - Testing Air Control Valve:

6. Release vacuum from air control valve chamber "B" and air switching valve, then apply vacuum directly to air control valve chamber "A", Fig. 82. Compressed air should be discharged from by-pass hose at idle.

7. Connect suitable air pump tester to check valve air hose.

8. Apply vacuum directly to air control valve chamber "A" and air switching valve.

9. Close off tester orifice.

10. Gradually increase engine speed and measure relief valve opening pressure. Opening pressure should be 3.3 to 5.6 psi.

11. Remove tester and reconnect air and vacuum hoses to proper locations.

1981-82 3T-C Engine
1. Disconnect air hose from check valve and air by-pass hose from air cleaner.

2. Disconnect vacuum hoses from air control and air switching valves.

Fig.83 - Testing Air Control Valve:

3. With engine idling, apply vacuum directly to air control valve chamber "B" and air switching valve chamber "A", Fig. 83. Compressed air should be discharged from air by-pass hose at idle.

Fig.84 - Testing Air Control Valve:

4. Release vacuum from air control valve chamber "B" and apply vacuum directly to air control valve chamber "A" and air switching valve chamber "A", Fig. 84. Compressed air should be discharged from air hose to check valve at idle.

Fig.85 - Testing Air Control Valve:

5. Release vacuum from air switching valve chamber "A" and apply vacuum directly to air control valve chamber "A", Fig. 85. Compressed air should be discharged from by-pass hose at idle.

6. Connect suitable tester to check valve air hose.

7. Apply vacuum directly to air control valve chamber "A" and air switching valve chamber "A".

8. Close off orifice of tester.

9. Gradually increase engine speed and measure relief valve opening pressure. Opening pressure should be 4.7 to 6.8 psi.

10. Remove tester and reconnect air and vacuum hoses to proper locations.