Air Injection Pump: Testing and Inspection

Fig.63 - Air Pump Discharge Pressure Test:

Fig.64 - Air Pump Discharge Pressure Test:

Fig.65 - Air Pump Discharge Pressure Test:

1. Check air pump for abnormal noise.

2. Check air pump discharge pressure as follows:

a. Connect tester, Figs. 63-65, to engine.

b. Start engine and raise speed as specified:

1968-71 3K-C 2200 RPM
1968-69 3R-C 1250 RPM
1973-74 4M 1350 RPM
1974 2T-C 1950 RPM
1975-76 & 1978-79 4M 1750 RPM
1975-82 Exc. 4M 1800 RPM

c. With engine running at the specified speed, the tester should indicate the green zone.

d. On all 1975-82 engines, if tester indicates in the red zone, the pump assembly is defective.

e. On 1969-74 engines, if tester indicates in the red zone close relief valve outlet with hand and recheck. If tester indicates in the green zone, the relief valve is defective. If tester still indicates in the red zone, the air pump assembly is defective.