Pontiac FIREBIRD 1972 Service Manual page 761

6D- 18
1972 PONTIAC SERVICE MANUAL
Fig. 6D-3 1 Checking for Vacuum Signal at Diverter Valve
Fig. 6D-32 Momentary Blast of Air Through Diverter Valve
During Engine Over-Run
DIVERTER VALVE
INSPECTION
1. Check condition and routing of all lines especially the
signal line. All lines must be secure, without crimps
and not leaking.
2. Disconnect signal line at valve. A vacuum signal
must be available with engine running (Fig. 31).
3. With engine stabilized at idle speed, no air should be
escaping through the muffler. Manually open and
quickly close the throttle, a momentary blast of air
should discharge through muffler for at least one
second (Fig. 6D-32).
4. Defective valves should be replaced.
REMOVE
1. Disconnect vacuum signal line. Disconnect valve ex-
haust hose.
2. Remove diverter valve from pump or elbow.
INSTALL
1. Install diverter valve to pump or elbow with new
gasket. Torque valve attaching screws to 85 lb. in.
2. Install outlet and vacuum signal lines and check sys-
tem for leaks.
AIR INJECTION PUMP
INSPECTION
Accelerate engine to approximately 1500 RPM and ob-
serve air flow from hose(s). If air flow increases as engine
is accelerated, pump is operating satisfactorily. If air flow
does not increase or is not present, proceed as follows:
1. Check for proper drive belt tension.
2. Check for a leaky pressure relief valve. Air may be
heard leaking with the pump running.
NOTE: The A.I.R. System is not completely
noiseless. Under nonnal conditions noise rises
in pitch as engine speed increases. To determine
if excessive noise is the fault of the Air Injection
Reactor System, operate the engine with the
pump drive belt removed. If excessive noise
does not exist with the belt removedproceed as
follows:
3. Check for a seized Air Injection Pump.
4. Check hoses, tubes and all connections for leaks and
proper routing.
5. Check air injection pump for proper mounting.
6. If none of the above conditons exist and the air injec-
tion pump has excessive noise remove and replace
pump unit.
REMOVE
1. Disconnect the hoses at the pump.
2. Remove pump pulley as outlined.
3. Remove pump mounting bolts and remove pump.