Chevrolet 10 Series 1970 Service Manual page 391

F ig . 14—M o m e n ta ry Blast o f A ir Through D iv e rte r
V a lv e D urin g Engine O ve r-R u n
DIVERTER VALVE
Inspection
• Check condition and routing o f a ll lines esp ecia lly
the signal line. A ll lin es must be secure, without
crim p s and not leaking.
• Disconnect signal line at va lv e . A vacuum signal
must be availab le with engine running (fig .
• With engine stab ilized at idle speed, no a ir should
be escaping through the m u ffler. Manually open and
quickly close the th rottle, a m om entary blast o f a ir
should discharge through m u ffler fo r at lea st one
second (fig, 14).
• D efective va lv es should be replaced.
CAUTION: D iv e r te r v a lv e s although som etim es
s im ila r in appearance
p articu lar requirem en ts
th e re fo re , be sure to install the c o rre c t va lve.
Replacement
• Disconnect vacuum signal line.
exhaust h ose(s).
• R em ove d iv e rte r va lve fro m pump.
• Install d iv e rte r valve to pump o r bracket with new
gasket. Torque valve attaching screw s to 85 in. lbs.
• Install outlet and vacuum signal lin es and check s y s ­
tem fo r leaks.
AIR INJECTION TUBE
Inspection (Fig. 1 5)
• T h ere is no p erio d ic s e r v ic e o r inspection fo r the
a ir injection tubes, yet on V8 engines whenever the
exhaust m anifolds a re
injection tubes fo r carbon build up and warped o r
burnt tubes.
• Rem ove any carbon build up with a w ire brush.
• W arped or burnt tubes must be replaced.
13).
a re designed to m eet
o f variou s engines,
Disconnect va lve
rem oved, inspect the a ir
Replacement
• On V8 engines clamp exhaust m anifold in a vise, r e ­
move carbon from tubes and using penetrating oil,
w ork tubes out o f m anifold.
• Install new tubes in m anifold.
AIR INJECTION PUMP
Inspection
A c c e le ra te engine to approxim ately 1500 R P M and ob­
s e rv e a ir flow fro m hose(s).
engine is accelera ted , pump is operating sa tis fa cto rily.
If a ir flow does not in crease o r is not present, proceed
as follow s:
• Check fo r p ro p er d rive belt tension.
• Check fo r a leaky p ressu re r e lie f va lve. A ir may be
heard leaking with the pump running.
NOTE: The A .I.R . System is not com pletely
n oiseless. Under norm al conditions noise r is e s
in pitch as engine speed increases.
mine if ex ces sive noise is the fault o f the A ir
In jector R ea ctor System,
with the pump d rive belt rem oved. If ex ce ssiv e
noise does not exist with the belt rem oved p ro ­
ceed as follow s:
• Check fo r a seized A ir Injection Pump.
• Check hoses, tubes, a ir m anifolds and a ll connec­
tions fo r leaks and p rop er routing.
• Check a ir injection pump fo r p rop er mounting.
• If none o f the above conditions exist and the a ir in ­
jection pump has exce ssive noise rem ove and r e ­
place pump unit.
Replacement
• Disconnect the hoses at the pump.
• Rem ove pump pulley as outlined.
• R em ove pump mounting bolts and rem ove pump.
• Install pump with mounting bolts loose.
• Install pump pulley as outlined.
• Install and adjust belt as outlined.
• Connect the hoses at the pump.
• Tighten mounting bolts secu rely.
Pressure Relief V a lv e Replacement
NOTE: The p ressu re r e lie f valve is in c o rp o r­
ated in the d iv e rte r valve. The com plete unit
must be replaced to c o rre c t a malfunction o f the
r e lie f valve.
EMISSION CONTROL SYSTEMS 6T-7
If a ir flow in crea ses as
T o d e te r­
operate the engine
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