Air Suction (As) System - Toyota 4-Runner 1985 Repair Manual

VCV
A
B
EMISSION CONTROL SYSTEMS (CARB.) - Air Suction (AS) System
Resonator
Reed Valve
VTV
AIR SUCTION (AS) SYSTEM
(Federal and Canada)
A03061
EC-43
EC1054
EC10SS
To reduce HC and CO emissions, this system draws in air into exhaust ports to accelerate oxidation, using vacuum generated
by the exhaust pulsation in the exhaust manifold.
Condition
Intake Manifold
Vacuum in VCV
Air Switching
AS
Vacuum Chamber A and B
Valve
Normal driving
-
Same OPEN ON
Full load driving Low vacuum Same
*
1 CLOSED OFF
*2
High vacuum acts on Momentarily
Sudden deceleration High vacuum
chamber B
CLOSED
OFF
Remarks:
* 1
The air switching valve shuts off gradually by the VTV.
*2
After a few seconds, vacuum in both chambers of the VCV equalize through the orifice.