Page 1169 of 2389
INSPECTION OF FUEL VAPOR LINES,
FUEL
TANK AND TANK CAP
1. VISUALLY INSPECT LINES AND CONNECTIONS
Look for loose connections, sharp bends or damage.
2. VISUALLY INSPECT FUEL TANK
Look for deformation, cracks or fuel leakage.
To reduce HC emissions, evaporated fuel from the fuel tank is routed through the charcoal canister to the intake manifold for
combustion in the cylinders.
3. VISUALLY INSPECT FUEL TANK CAP
Check if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
FUEL EVAPORATIVE EMISSION CONTROL (EVAP) SYSTEM
HC from canister is led into air
intake chamber. HC from tank is absorbed into
the canister.
HC from tank is absorbed
into the canister. Positioned below
purge port
Positioned above
purge port
Air is led into the fuel tank. Throttle Valve
OpeningEvaporated Fuel (HC) Canister Check Valve
Check
Valve in
Cap
Coolant
Te m p .BVSV
± EMISSION CONTROL SYSTEMS (2VZ±FE)Emission Control (EVAP) SystemEC±17
Page 1170 of 2389

5. CLEAN FILTER IN CANISTER
Clean the filter by blowing 3 kg/cm
2 (43 psi, 294 kPa) of air
into the tank pipe while holding the other upper canister pipe
closed.
HINT
wDo not attempt to wash the canister.
wNo activated carbon should come out.
6. REINSTALL DUST COVER TO CHARCOAL CANISTER
7. REINSTALL CHARCOAL CANISTER
INSPECTION OF BVSV CHECK BVSV
BY BLOWING AIR INTO PIPE
(a) Drain the coolant from the radiator into a suitable container.
(b) Remove the BVSV from the water by±pass outlet.
(c) Cool the BVSV to below 35°C (95°f) with cool water.
(d) Blow air into a pipe and check that the BVSV is closed.
(e) Heat the BVSV to above 54°C (129°F) with hot water.
(f) Blow air into a pipe and check that the BVSV is open.
If a problem is found, replace the BVSV.
(g) Apply adhesive to two or three threads of the BVSV, and re-
install.
Adhesive: Part No. O8833±00070, THREE BOND
1324 or equivalent
(h) Refill the radiator with coolant.
INSPECTION OF CHARCOAL
CANISTER
1. REMOVE CHARCOAL CANISTER
2. REMOVE DUST COVER FROM CHARCOAL CANISTER
3. VISUALLY INSPECT CHARCOAL CANISTER
Look for cracks or damage.
4. CHECK FOR CLOGGED FILTER AND STUCK CHECK
VA LV E
(a) Using low pressure. compressed air, blow into the tank pipe
and check that air flows without resistance from the other
pipes.
(b) Blow into the purge pipe and check that air¿does not flow
from the other pipes.
If a problem is found, replace the charcoal canister.
± EMISSION CONTROL SYSTEMS (2VZ±FE)Fuel Evaporative Emission Control (EVAP) SystemEC±18
Page 1171 of 2389
To reduce NC and CO emissions, when decelerating the dash pot opens the throttle valve slightly more than at idle.
This causes the air±fuel mixture to bum completely.
DASH POT (DP) SYSTEM
(MT only)
Slightly opens and then slowly closes to idle
position Pushed in by return force of throttle valve
Pushed in by return force of throttle valvePushed out by diaphragm springHigh speed position Idle speed positionThrottle Valve
Normal driving
DecelerationDiaphragm
Condition
CLOSED
CLOSED Idling
OPENVTV
± EMISSION CONTROL SYSTEMS (2VZ±FE)Dash Pot (DP) System (MT only)EC±19
Page 1172 of 2389
INSPECTION OF DASH POT (DP)
SYSTEM
1. WARM UP ENGINE
Allow the engine to normal operating temperature.
2. CHECK IDLE SPEED
Idle speed: 700 rpm
3. REMOVE CAP, FILTER AND SEPARATOR FROM DP
4. CHECK DP SETTING SPEED
(a) Maintain the engine at 2,500 rpm.
(b) Plug the VTV hole, with your finger.
If not as specified, adjust with the DP adjusting screw.
5. REINSTALL DP SEPARATOR, FILTER AND CAP
HINT: Install the filter with the coarser surface facing the at-
mospheric side (outward).
6. CHECK VTV OPERATION
Race the engine at 2,500 rpm for a few seconds, release
the throttle valve and check that the engine returns to idle in
a few seconds.(c) Release the throttle valve.
(d) Check that the DP is set.
DP setting speed: 2,000 rpm
(w/ Cooling fan OFF)
± EMISSION CONTROL SYSTEMS (2VZ±FE)Dash Pot (DP) System (M T only)EC±20
Page 1173 of 2389
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
± EMISSION CONTROL SYSTEMS (2VZ±FE)Exhaust Gas Recirculation (EGR) SystemEC±21
Page 1174 of 2389

(c) Disconnect the vacuum hose from the R port of the EGR
vacuum modulator and connect the R port directly to the
intake manifold with another hose.
(d) Check that the vacuum gauge indicates high vacuum at
3,500 rpm.
HINT: As large amount of EGR gas enters, the engine will
misfire slightly.
(e) Remove the vacuum gauge and reconnect the vacuum
hoses to the proper locations.
INSPECTION OF EGR SYSTEM
1. CHECK AND CLEAN FILTERS IN EGR VACUUM
MODULATOR
(a) Check the filters for contamination or damage.
(b) Using compressed air, clean the filters.
HINT: Install the filters with the coarser surface facing the at-
mospheric side (outward).
2. PREPARATION
Using a 3±way connector, connect a vacuum gauge to the
hose between the EGR valve and vacuum pipe.
3. CHECK SEATING OF EGR VALVE
Start the engine and check that the engine starts and runs at
idle.
4. CHECK6VSV WITH COLD ENGINE
(a) The coolant temperature should be below 40
°C
(104°F).
(b) Check that the vacuum gauge indicates zero at
2,500 rpm.
5. CHECK6VSV AND EGR VACUUM MODULATOR
WITH HOT ENGINE
(a) Warn n up the engine.
(b) Check that the vacuum gauge indicates low vacuum at 2,500
rpm.
± EMISSION CONTROL SYSTEMS (2VZ±FE)Exhaust Gas Recirculation (EGR) SystemEC±22
Page 1175 of 2389

INSPECTION OF EGR VACUUM
MODULATOR
CHECK EGR VACUUM MODULATOR OPERATION
(a) Disconnect the vacuum hoses from ports P, Q and R
of the EGR vacuum modulator.
(b) Block ports P and R with your finger.
(e) Blow air into port Q, and check that the air passes through
to the air filter side freely.
(d) Start the engine, and maintain speed at 3,500 rpm.
(e) Repeat the above test. Check that there is a strong
resistance to air flow.
(f) Reconnect the vacuum hoses to the proper locations.
INSPECTION OF EGR VALVE
1. REMOVE EGR VALVE
Check for sticking and heavy carbon deposits.
If a problem is found, replace the valve.
2. REINSTALL EGR VALVE
Install a new gasket.
INSPECTION OF BVSV
CHECK BVSV BY BLOWING AIR INTO PIPE
(a) Drain the coolant from the radiator into a suitable container.
(b) Remove the BVSV from the water by±pass outlet.
(e) Cool the BVSV to below 40
°C (104°F) with cool water.
(d) Blow air into the pipe, and check that the BVSV is
closed.
(e) Heat the BVSV to above 54
°C (129°F) with hot water.
(f) Blow air into the pipe, and check that the BVSV is
open.
If a problem is found, replace the BVSV.
(g) Apply adhesive to two or three threads of the BVSV,
and reinstall.
Adhesive: Part No. 08833±00070, THREE BOND
1324 or equivalent
(h) Refill the radiator with coolant. 6. CHECK EGR VALVE
(a) Apply vacuum directly to the EGR valve with the engine id-
ling.
(b) Check that the engine runs rough or dies.
(c) Reconnect the vacuum hoses to the proper locations.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION,
SYSTEM IS OK; OTHERWISE INSPECT EACH PART
± EMISSION CONTROL SYSTEMS (2VZ±FE)Exhaust Gas Recirculation (EGR) SystemEC±23
Page 1176 of 2389
INSPECTION OF EXHAUST PIPE
ASSEMBLY
1. CHECK CONNECTIONS FOR LOOSENESS OR
DAMAGE
2. CHECK CLAMPS FOR WEAKNESS, CRACKS OR
DAMAGE
INSPECTION OF CATALYTIC
CONVERTER
CHECK FOR DENTS OR DAMAGE
If any part of protector is damaged or dented to the extent
that it contacts the converter, repair or replace it.
To reduce HC, CO and NOx emissions, they are oxidized, reduced and converted to nitrogen (NO, carbon dioxide (C02)
and water (H20) by the catalyst.
THREE±WAY CATALYST (TWC) SYSTEM
OXIDATION
AND
REDUCTIONOXIDATION
AND
REDUCTION HC, CO AND
NOxExhaust Gas
Exhaust Port
C02
H2O
N
2
Main TWC
Sub±TWC
± EMISSION CONTROL SYSTEMS (2VZ±FE)Three±Way Catalyst (TWC) SystemEC±24