EC–1

EMISSION CONTROL SYSTEMS (3S–FE) –

EMISSION CONTROL SYSTEMS

EC–2
EMISSION CONTROL SYSTEMS (3S–FE) – System Purpose

SYSTEM PURPOSE
System Abbreviation Purpose

Positive crankcase ventilation PCV Reduced blow–by gas (HC)

Fuel evaporative emission control EVAP Reduced evaporative HC
Exhaust gas recirculation EGR Reduces NOx
Three–way catalyst TWC Reduces HC1 CO and NOx
Electronic fuel injection* EFI Regulates all engine conditions for reduction of
exhaust emissions.

Remarks *For inspection and repair of the EFI system, refer to the EFI section of this manual.
 EC–3
EMISSION CONTROL SYSTEMS (3S–FE) – Component Layout and Schematic Drawing

COMPONENT LAYOUT AND SCHEMATIC DRAWING

EC–4
EMISSION CONTROL SYSTEMS (3S–FE) – Positive Crankcase Ventilation (PCV) System

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM

To reduce HC emission, crankcase blow–by gas (HQ is routed to the intake manifold for combustion in the cylinders.

INSPECTION OF PCV HOSE AND

CONNECTIONS
VISUALLY INSPECT HOSE AND CONNECTIONS
Check for cracks, leaks, or damage.
 EC–5
EMISSION CONTROL SYSTEMS (3S–FE) – Fuel Evaporative Emission Control (EVAP) System

FUEL EVAPORATIVE EMISSION CONTROL (EVAP) SYSTEM

To reduce HC emission, evaporated fuel from the fuel tank is routed through the charcoal canister to the intake manifold for
combustion in the cylinders.

Canister Check Valve Check

Coolant Throttle Valve Evaporated Fuel (HO
Valve in
Temp. svsv Opening
Cap
Below
35°C (95°F) NC from tank is absorbed into
the canister.
Above
54°C(129° F ) HC from canister is led into air
intake chamber.
High pressure HC from tank is absorbed into
in tank the canister.
High vacuum Air is led into the fuel tank.
in tank

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.

3. VISUALLY INSPECT FUEL TANK CAP

Check if the cap and/or gasket are deformed or damaged if
necessary, repair or replace. the cap.
EC–6
EMISSION CONTROL SYSTEMS (3S–FE) – Fuel Evaporative Emission Control (EVAP) System

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

VALVE
(a) Using low pressure compressed air, blow into the tank pipe
and check that air flows without resistance from the other
pipes.
(b) Slow into the purge pipe and check that air does not flow
from the other pipes.
If a problem is found, replace the charcoal canister.

5. CLEAN FILTER IN CANISTER

Clean the filter by blowing 3 kg/cm2 (43 psi, 294 kPa) of
compressed air into the tank pipe while holding the other up-
per canister pipe closed.
HINT:
• Do not attempt to wash the canister.
• No 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.
(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. 08833–00070, THREE BOND
1324 or equivalent
(h) Refill the radiator with coolant.
 EC–7
EMISSION CONTROL SYSTEMS (3S–FE) – Fuel Evaporative Emission Control (EVAP) System

INSPECTION OF JET (M/T only)

CHECK JET BY BLOWING AIR FROM EACH SIDE
Check for stoppage.
EC–8
EMISSION CONTROL SYSTEMS (3S–FE) – Exhaust Gas Recirculation (EGR) System

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

 EC–9
EMISSION CONTROL SYSTEMS (3S–FE) – Exhaust Gas Recirculation (EGR) System

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

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 45°C
(113° F).
(b) Check that the vacuum gauge indicates zero at 2,500
rpm.

5. CHECK6VSV AND EGR VACUUM MODULATOR WITH

HOT ENGINE
(a) Warm up the engine.
(b) Check that the vacuum gauge indicates low vacuum at
2,500 rpm.

(e) Disconnect the vacuum hose from port R of the EGR

vacuum modulator and connect port R directly to the in-
take manifold with another hose.
(d) Check that the vacuum gauge indicates high vacuum at
2,500 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.
EC–10
EMISSION CONTROL SYSTEMS (3S–FE) – Exhaust Gas Recirculation (EGR) System

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.
(e) Reconnect the vacuum hoses to the proper locations.
IF NO PROBLEM IS FOUND WITH THIS INSPECTION,
SYSTEM IS OK; OTHERWISE INSPECT EACH PART

INSPECTION OF BVSV
CHECK BVSV BY SLOWING AIR INTO PIPE
(a) Drain the coolant from the radiator into a suitable container.
(b) Remove the BVSV from the water outlet.
(e) Cool the BVSV to below 45°C (113°F) with cool water.
(d) Check that air flows from pipe J to the air filter.

(e) Heat the BVSV to above 66°C (51°F) with hot water.
(f) Check that air flows from pipe J to pipe K.
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.

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 2,500 rpm.
(e) Repeat the above test. Check that there is a strong
resistance to airflow.
(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.
 EC–11
EMISSION CONTROL SYSTEMS (3S–FE) – Three–Way Catalyst (TWC) System

THREE–WAY CATALYST (TWC) SYSTEM

To reduce HC, CO and NOx emissions, they are oxidized, reduced and converted to nitrogen (N2), carbon dioxide (C02)
and water (H20) by the catalyst.

Exhaust Port Main TWC Sub–TWC Exhaust

Gas
OXIDATION OXIDATION AND c02
HC, CO AND REDUCTION
AND H2O
NOx
REDUCTION N2
INSPECTION OF EXHAUST PIPE
ASSEMBLY
CHECK CONNECTIONS FOR LOOSENESS OR DAMAGE
REPLACEMENT OF CATALYTIC
CONVERTERS
1. REMOVE CONVERTERS
(a) Jack up the vehicle.
(b) Check that the converter is cool.
(e) Remove the suspension lower crossmember.
(See page EM–44)
(d) Remove the front exhaust pipe (Sub–converter).
• Loosen the bolt, and disconnect the clamp the
exhaust pipe bracket.
• Remove the three nuts, and remove the exhaust pipe. Remove
the three nuts, and remove the exhaust pipe. Remove the gas-
ket.
(e) Remove the two bolts, two nuts and two converter stays.
(f) Remove the three bolts, two nuts, gasket, retainer, cushion and
main converter.
(g) Remove the eight bolts and two heat insulators from the main
converter.
EC–12
EMISSION CONTROL SYSTEMS (3S–FE) – Way Catalyst (TWC) System

2. INSTALL CONVERTERS
(a) Install the two heat insulators to the main converter with the
nine bolts.
(b) Place a new cushion, retainer and gasket on the main con-
verter.
(e) Install the main converter with the three bolts and two nuts.
Torque the bolts and nuts.
Torque: 300 kg–cm (21 ft–Ib, 29 N–m)
(d) Install the two converter stays with the two bolt and two nuts.
Torque: 650 kg–cm (46 ft–lb, 64 N–m)
(e) Install the front exhaust pipe (Sub–converter).
• Place new two gaskets on the exhaust pipe.
• Install the exhaust pipe with the two bolts and five nuts.
Torque: To converter 630 kg–cm (46 ft–Ib, 63 N–m)
To center exhaust pipe
440 kg–cm (32 ft–lb, 43 N–m)
• Install the exhaust pipe clamp with the bolt.
(f) Install the suspension lower crossmember
(See page EM–50)
 EC–13
EMISSION CONTROL SYSTEMS (2VZ–FE) – System Purpose

SYSTEM PURPOSE
System Abbreviation Purpose

Positive Crankcase ventilation PCV Reduces blow–by gas (HC)

Fuel evaporative emission control EVAP Reduces evaporative HC
Dash pot DP Reduces HC and CO
Exhaust gas recirculation EGR Reduces NOx
Three–way catalyst TWC Reduces HC, CO and NOx
Electronic fuel injection* EFI Regulates all engine conditions for reduction of
exhaust emissions.

Remarks *For inspection and repair of the EFI system, refer to EFI section of this
manual.
EC–14
EMISSION CONTROL SYSTEMS (2VZ–FE) – Component Layout and Schematic Drawing

COMPONENT LAYOUT AND SCHEMATIC DRAWING

 EC–15
EMISSION CONTROL SYSTEMS (2VZ–FE) – Positive Crankcase Ventilation (PCV) System

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM

To reduce HC emission, crankcase blow–by gas (HC) is routed through the PCV valve to the air intake
chamber for combustion in the cylinders.
Engine not Running or Backfiring Normal Operation

Idling or Deceleration Acceleration or High Load

EC–16
EMISSION CONTROL SYSTEMS (2VZ–FE) – Crankcase Ventilation (PCV) System

INSPECTION OF PCV VALVE

1. REMOVE PCV VALVE
2. INSTALL CLEAN HOSE TO PCV VALVE
3. BLOW FROM CYLINDER HEAD SIDE
Check that air passes through easily.
NOTICE: Do not suck air through the valve.
Petroleum substances inside the valve are harmful.

4. BLOW FROM AIR INTAKE CHAMBER SIDE

Check that air passes through with difficulty.
If the PCV valve fails either of the checks, replace it.
5. REMOVE CLEAN HOSE FROM PCV VALVE
6. REINSTALL PCV VALVE

INSPECTION OF PCV HOSE AND

CONNECTIONS
VISUALLY INSPECT HOSE AND CONNECTIONS
Check for cracks, leaks, or damage.
 EC–17
EMISSION CONTROL SYSTEMS (2VZ–FE) – Emission Control (EVAP) System

FUEL EVAPORATIVE EMISSION CONTROL (EVAP) SYSTEM

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.

Canister Check Valve Check

Coolant Throttle Valve Evaporated Fuel (HC)
BVSV Opening Valve in
Temp. Cap

HC from tank is absorbed into

the canister.
Positioned below
purge port

Positioned above HC from canister is led into air

purge port intake chamber.

HC from tank is absorbed

into the canister.

Air is led into the fuel tank.

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.

3. VISUALLY INSPECT FUEL TANK CAP

Check if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
EC–18
EMISSION CONTROL SYSTEMS (2VZ–FE) – Fuel Evaporative Emission Control (EVAP) System

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

VALVE
(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.

5. CLEAN FILTER IN CANISTER

Clean the filter by blowing 3 kg/cm2 (43 psi, 294 kPa) of air
into the tank pipe while holding the other upper canister pipe
closed.
HINT
• Do not attempt to wash the canister.
• No 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.
 EC–19
EMISSION CONTROL SYSTEMS (2VZ–FE) – Dash Pot (DP) System (MT only)

DASH POT (DP) SYSTEM

(MT only)

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.

Diaphragm VTV Throttle Valve

Condition
Pushed in by return force of throttle valve Idle speed position
Idling CLOSED

Normal driving Pushed out by diaphragm spring OPEN High speed position

Pushed in by return force of throttle valve Slightly opens and then slowly closes to idle
Deceleration CLOSED position
EC–20
EMISSION CONTROL SYSTEMS (2VZ–FE) – Dash Pot (DP) System (M T only)

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.

(c) Release the throttle valve.

(d) Check that the DP is set.
DP setting speed: 2,000 rpm
(w/ Cooling fan OFF)

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.
 EC–21
EMISSION CONTROL SYSTEMS (2VZ–FE) – Exhaust Gas Recirculation (EGR) System

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

EC–22
EMISSION CONTROL SYSTEMS (2VZ–FE) – Exhaust Gas Recirculation (EGR) System

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.

(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.
 EC–23
EMISSION CONTROL SYSTEMS (2VZ–FE) – Exhaust Gas Recirculation (EGR) System

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

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.
EC–24
EMISSION CONTROL SYSTEMS (2VZ–FE) – Three–Way Catalyst (TWC) System

THREE–WAY CATALYST (TWC) SYSTEM

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.

Exhaust Port Main TWC Sub–TWC Exhaust Gas

OXIDATION C02
OXIDATION
HC, CO AND H2O
AND AND
NOx N2
REDUCTION REDUCTION

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.
 EC–25
EMISSION CONTROL SYSTEMS (2VZ–FE) – Three–Way Catalyst (TWC) System

INSPECTION OF HEAT INSULATOR

1. CHECK HEAT INSULATOR FOR DAMAGE
2. CHECK FOR ADEQUATE CLEARANCE BETWEEN
CATALYTIC CONVERTER AND HEAT INSULATOR

REPLACEMENT OF CATALYTIC
CONVERTER
1. REMOVE CONVERTER
(a) Jack up the vehicle.
(b) Check that the converter is cool.
(c) Remove the four bolts and nuts holding the pipes to the con-
verter.
(d) Remove the converter and two gaskets.
2. REINSTALL CONVERTER
(a) Place new two gaskets on the front and rear pipes.
(b) Install the converter with the bolts and nuts. Torque the bolts
and nuts. ,
Torque: 440 kg–cm (32 ft–Ib, 43 N–m)