Toyota TERCEL 1985 Repair Manual page 108

EC-20 EMISSION CONTROL SYSTEMS - Exhaust Gas Recirculation (EGR) System
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
(USA Vehicles and Canadá 3A-C Engine 4-Speed & Wagón A/T)
(1)
.Check Valve
EGR Port
EGR Vacuum
Modulator
Pressure Chamber
To reduce NOx emission, part of thé exhaust gases is recirculated through the EGR valve to the intake manifold to
lower the máximum combustión temperature.
Cooiant Temp. TVSV
Below 50°C OPEN
(122°F) (J-M)
Above 68°C
OPEN
(154°F)
(M-K)
•
5rü
EGR Valve
EGR Vacuum
Modulator
TVSV
EC0451
Throttle Valve Pressure in EGR
Opening Angle
Valve Pressure Chamber
—
Positioned below
EGR port
(1) * Pressure continuously
Positioned
LOW alternating
above EGR
between low
port
(2)
and high
HIGH
r r n ,
U 9 C 3 - "
c u n v ralve el
if/í
^ G a s Filter
^ C h e c k Valve
(2)
EGR Vacuum
Modulator
Pressure Chamber
EGR Vacuum
Modulator
—
—
— —
Opens passage
to atmosphere
Closes passage
to atmosphere
I V I U U U i a i U I
opens •*—Pres
EGR Valve Exhaust Gas
CLOSED Not recirculated
CLOSED Not recirculated
CLOSED Not recirculated
OPEN Recirculated
]
auie ui v|j»—-
ECO450
EC0452