Fuel Evaporative Emission Control (Evap) System - Toyota 4-Runner 1985 Repair Manual

EMISSION CONTROL SYSTEMS (CARB ) _ Fuel Evaporative Emission Control
. (EV AP) System
EC-21
FUEL EVAPORATIVE EMISSION CONTROL (EVAP) SYSTEM
USA
T
I
!
Charcoal
Canister
(for Carburetor)
Canada
"--1+
Thermo Switch (1)
VSV
(Open)
Charcoal
Canister
(for Fuel Tank)
~heCk
Fuel Tank Valve
Charcoal
Canister
~heCk
Fuel Tank Valve
A03039
EC0995 EC0996
To reduce
He
emissions, evaporated fuel from the fuel tank and float chamber is routed through the charcoal canister
to the intake manifold for combustion in the cylinders.
*Outer
Coolant Thermo Vehicle Com-
Check Valve
Check
Evaporated Fuel
IG S/W Engine Vent Con-
VSV Valve
trol Valve
Temp. S/W
(1)
Speed puter
(1 )
(2)
in Cap
(He)
!
Not
HC from tank and
OFF
i
running
OPEN - - - - - - - -
float chamber is
absorbed into the
canister.
Below 43°C
ON - OFF CLOSED
(109°F)
-
- -
HC from tank is
absorbed into the
Below 7 mph
OFF CLOSED
- - -
canister
ON Running
CLOSED (11 km/h)
Above 55°C
OFF
(131°F)
Above HC from canister
16 mph ON OPEN
-
-
-
is led into the intake
(25 km/h) manifold.
HC from tank is
High pressure in tank - - -
- -
-
OPEN CLOSED CLOSED absorbed into the
canister.
High vacuum in tank
- - -
-
-
- CLOSED OPEN OPEN
( A;, ;, led ;nto the
1
tank.
Remarks:
*The outer vent control valve is pulled by intake manifold vacuum and held by the solenoid.
The solenoid itself cannot pull the valve.
ECll03
INSPECTION OF FUEL FILLER CAP, FUEL VAPOR
LINES AND FUEL TANK
1 . VISUALLY INSPECT FUEL FILLER CAP
Look for damaged or deformed gasket and cap.
If a problem is found, repair or replace the cap.