Toyota 4-Runner 1985 Repair Manual page 144

EC-44
Air
EMISSION CONTROL SYSTEMS (CARB.) - Air Suction (AS) System
EC1056
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No Bubbling Noise
EC1057
EC1058
Vacuum
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Air
EC1096
INSPECTION OF AS SYSTEM
1. VISUALLY CHECK HOSES AND TUBES FOR CRACK
KINKS, DAMAGE OR LOOSE CONNECTIONS
2. DISCONNECT AIR SUCTION HOSE FROM AIR
SWITCHING VALVE
3. CHECK AIR SWITCHING VALVE
(a) Check that a bubbling noise is heard from the air
switching valve at idle.
(b) Disconnect the vacuum hose from the air switching
valve.
(c) Check that a bubbling noise is not heard from the air
switching valve at idle.
(d) Reconnect vacuum hose.
A03062
4. CHECK VCV
Race the engine and quickly close the throttle valve. Check
that the bubbling noise stops momentarily.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION, THE:
SYSTEM IS OKAY; OTHERWISE INSPECT EACH PART
INSPECTION OF AIR SWITCHING VALVE
CHECK AIR SWITCHING VALVE BY BLOWING AIR INTO PIPE
(a) Apply vacuum to the air switching valve diaphragm.
(b) Blow air into a pipe and check that the air switching
valve is open.
(c) Release the vacuum and check that the air switching
valve is closed.
INSPECTION OF VCV
CHECK VCV OPERATION
(a) Disconnect the vacuum hose from port Z of the VCV.
(b) Connect port Z directly to the intake manifold with
another hose, and disconnect the vacuum hoses fr,---
ports S and X of the VCV.
(c) With the engine idling, place your finger over port X
and check that vacuum is not felt.
EC1059
(d) Check that vacuum is felt momentarily as the vacu-
' - - - -_ _ _ _ _ _ _ _ _ _ _ _ _ ---J
urn hose is reconnected to port S.