Chevrolet CHEVY VAN G10 SERIES Service Manual page 210

EMISSION CO N TR O L SYSTEM 6T-18
Fig. 6 T -3 2 —Rem oving Check Valve
Replacement
• D isconnect pum p o u tlet hose a t check valve. Remove
check valve from air m anifold, being careful not to bend
or tw ist air m anifold (Fig. 6T-32).
D IV ER TER V A LV E
Inspection
• Check co nditio n and routing o f all lines especially the
signal line. All lines m ust be secure, w ithout crim ps and
n o t leaking.
• D isconnect signal line at valve. A vacuum signal m ust be
available w ith engine running (Fig. 6T-33).
• W ith engine stabilized at idle speed, no air should be
escaping through th e m uffler. Manually open and quickly
close the th ro ttle , a m om entary blast o f air should
discharge through m uffler for at least one second (Fig.
6T-34).
• Defective valves should be replaced.
Fig. 6 T -3 3 —Checking fo r Vacuum Signal at Diverter Valve
Fig. 6 T -3 4 —M om entary Blast o f A ir Through Diverter Valve
During Engine Over-Run
C A U T IO N : Diverter
similar in appearance are designed to meet particular
requirements o f various engines, therefore, be sure
to install the correct valve.
Replacement
• D isconnect vacuum signal line. D isconnect valve exhaust
hose(s).
• Remove diverter valve from pum p or elbow.
• Install diverter valve to p um p or elbow w ith new gasket.
T orque valve attaching screws to 85 in. lbs.
• Install o u tlet and vacuum signal lines and check system
for leaks.
AIR INJECTION TUBE
Inspection (Fig. 6T-35)
• T here is no periodic service or inspection for th e air
injection tubes, yet on in-line engines w henever the
cylinder head is rem oved or on V
exhaust m anifolds are rem oved, inspect th e air injection
tubes for carbon build up and w arped or b urned tubes.
valves although sometimes
8
engines w henever the
C H E V Y V A N S H O P M A N U A L