Mixture Control (Mc) System - Toyota 4-Runner 1985 Repair Manual

EC-26 EMISSION CONTROL SYSTEMS (CARB.) -
Mixture Control (MC) System
MC Valve
CONSTANT RPM
Chamber A
Chamber B
MIXTURE CONTROL (MC) SYSTEM
(MIT Vehicles On'
A03044
EC0312
SUDDEN DECELERATION, STEP (1)
Chamber A
Chamber B
EC0313 EC0314
To reduce HC and CO emissions, this system allows air to enter the intake manifold on sudden deceleration.
Condition
Vacuum in Chambers A and B MC Valve Fresh Air
Constant RPM
Same vacuum CLOSED No air flow
Step (1)
High vacuum acts on chamber B OPEN
Air is routed through MC valve
to intake manifold.
Sudden deceleration
After a few seconds, vacuum in
Step (2)
both chambers equalizes through CLOSED No air flow
the orifice.