ect LEXUS SC300 1991 Service Repair Manual

SERVICE SPECIFICATIONS
SERVICE DATA
ThermostatValve opening temperature80±845C176±183 5F
Valve liftat 95 5C (203 5F) 10 mm0.39 in.
Radiator capRelief valve opening pressureSTD74±103 kPa
(0.75±1.05 kgf/cm, 10.7±14.9 psi)
Limit 59 kPa 0.6 kgf/cm 8.5 psi
On±vehicle
itifh
Oil pressure1,177±2,452 kPa
inspection for hy-
draulic cooling(12±25 kgf/cm, 171±356 psi)draulic cooling
fan
fan
Hydraulic pumpSpool valve45.8 mm1.803 in.
Rotor side clearanceSTD Drive rotor 0.02 mm0.0008 in.
Driven rotor 0.03 mm0.0012 in.
Limit Drive rotor 0.03 mm0.0012 in.
Driven rotor 0.04 mm0.0016 in.
Rotor body clearanceSTD 0.05±0.09 mm0.0020±0.0035 in.
Limit 0.10 mm0.0039 in.
Rotor tip clearanceSTD 0.02 mm0.0008 in.
Limit 0.03 mm0.0012 in.
Drive shaft bushing inside diameter17.00±17.05 mm0.6693±0.6713 in.
Drive shaft diameter16.97±16.98 mm0.6681±0.6685 in.
Drive shaft oil clearanceSTD 0.02±0.08 mm0.0008±0.0031 in.
Limit 0.08 mm0.0031 in.
Drive shaft preload (rotating torque)0.3 N Vm 3.0 kgf Vcm 2.6 in. Vlbf
Solenoid valve resistanceat cold 7.5±8.5

Hydraulic motorRotor side clearanceSTD0.01±0.04 mm0.0004±0.0016 in.
Limit 0.05 mm0.0020 mm
Drive shaft hole inside diameter14.000±14.011 mm0.5512±0.5516 in.
Drive shaft diameter13.973±13.984 mm0.5501±0.5506 in.
Drive shaft oil clearanceSTD 0.016±0.038 mm0.0006±0.0015 in.
Limit 0.04 mm0.0031 in.
Drive shaft preload (rotating torque)0.3 NVm 3.0 kgf Vcm 2.6 in. Vlbf
Water temp. Resistanceat 80 5C (176 5F)1.48±1.58 k

sensor
CO±64±
COOLIING SYSTEM Service Specifications
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EMISSION CONTROL SYSTEM
NOTE: The specification descriptions ºUSA Spec.º and
º Exc. USA Spec. º used in this section indicate the following
specifications.
USA Spec .: USA (50 States) Specifications
Exc. USA Spec .: USA (except California) and Canadian
Specifications.
EC±1
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DESCRIPTION
The emission control systems are installed to reduce the amount of HC, CO, \
and NOx emitted from the en-
gine, and to also prevent the release of evaporated fuel from the gasoline ta\
nk and prevent atmospheric release
of blow±by gas. The system consists of the PCV, EVAP, EGR and TWC.
The function of each system is shown in the following table.
 
System
 
Abbreviation
 
Purpose 
Positive crankcase ventilation
 
PCV
 
Reduces blow±by gas (HC) 
Fuel evaporative emission control
 
EVAP
 
Reduces evaporative HC 
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 sec\
tion.
COMPONENTS LAYOUT
EC±2±
EMISSION CONTROL SYSTEMS Description
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INSPECTION OF PCV VALVE
1. REMOVE PCV VALVE(a) Disconnect the PCV hose from the PCV valve.
(b) Remove the PCV valve.
2. INSTALL CLEAN HOSE TO PCV VALVE
3. INSPECT PCV VALVE OPERATION (a) Blow air into the cylinder head side, and check that airpasses through easily.
CAUTION: Do not suck air through the valve. Petroleum
substances inside the valve are harmful.
(b) Blow air into the air intake chamber side, and check that air passes through with difficulty.
If operation is not as specified, replace the PCV valve.
4. REMOVE CLEAN HOSE FROM PCV VALVE
5. REINSTALL PCV VALVE
INSPECTION OF PCV HOSE AND
CONNECTIONS
VISUALLY INSPECT HOSE, CONNECTIONS AND GASKETS Check for cracks, leaks or damage.
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EMISSION CONTROL SYSTEMS Positive Crankcase Ventilation (PVC) SystemEC±7
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FUEL EVAPORATIVE EMISSION CONTROL (EVAP) SYSTEM
DESCRIPTION
To reduce HC emission, evaporated fuel from the fuel tank is routed throug\
h the charcoal canister to the
intake manifold for combustion in the cylinders.
OPERATION
CoolantVSVThrottle ValveCanister Check ValveCheck
Valve inEvaporated F el (HC)Coolant
Te m p .VSVThrottle Valve
Opening(1)(2)(3)Valve inCapEvaporated Fuel (HC)
BelowNoFulley closedBelow
40 5C (104 5F)
No
OperationFulley closed.±±±±Small volume of HC from
Fully closed or
bellow Specified air
canister enters air intake
chamber.
Above
bellow Specified air
volume.±±±±chamber.
Above
40 5C (104 5F)Operation
Conditions other
than above.±±±±
HC from canister enters air
intake chamber in the amout
programmed in accordance
with the intake air volume.
High pres-
sure in tank±±±OPENCLOSEDCLOSEDHC from tank is absorbed
into the canister.
High vacuum
in tank±±±CLOSEDOPENOPENAir 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.
EC±8
±
EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) System
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3. VISUALLY INSPECT FUEL TANK CAPCheck if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
INSPECTION OF CHARCOAL CANISTER
1. REMOVE CHARCOAL CANISTER(a) Disconnect the following hoses:(1) Vacuum hose (from VSV) from charcoal canister
(2) EVAP hose from charcoal canister
(b) Disconnect the grommet on the check valve from the bracket, and remove the charcoal canister.
(c) Remove the check valve from the hose end on the charcoal canister.
2. VISUALLY INSPECT CHARCOAL CANISTER Look for cracks or damage.
3. CHECK FOR CLOGGED FILTER AND STUCK CHECK VA LV E
(a) Using low pressure compressed air, blow into port A and
check that air flows without resistance from the other
ports.
(b) Blow into port B and check that air does not flow from the
other ports.
If a problem is found, replace the charcoal canister.
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EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) SystemEC±9
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4. CLEAN FILTER IN CANISTERClean the filter by blowing 294 kPa (3 kgf/cm2, 43 psi) of com-
pressed air into port A while holding port B closed.
NOTICE:
w Do not attempt to wash the canister.
w No activated carbon should come out.
5. REINSTALL CHARCOAL CANISTER
HINT: Install the check valve with black port facing the char-
coal canister side.
(a) Install the check valve to the hose end on the charcoalcanister.
(b) Install the charcoal canister.
(c) Install the grommet on the check valve to the bracket.
(d) Connect the following hoses: (1) Vacuum hose (from VSV) to charcoal canister
(2) EVAP hose to charcoal canister
COMPONENTS FOR REMOVAL AND INSTALLATION OF VSV
EC±10±
EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) System
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INSPECTION OF VSV
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and the negative (±) termi-
nal cable is disconnected from the battery.
2. REMOVE INTAKE AIR CONNECTOR (a) Disconnect the following hoses:(1) Air hose (from ISC valve) from intake air connector
(2) Air hose (from PS air control valve) from intake air
connector
(b) Remove the bolt holding the intake air connector to the cylinder head cover.
(c) Loosen the two hose clamps.
(d) Disconnect the intake air connector from the throttle
body and air cleaner hose, and remove the intake air
connector.
3. REMOVE VSV (a) Disconnect the VSV connector.
(b) Disconnect the following hoses:(1) Vacuum hose (from vacuum pipe) from VSV
(2) Vacuum hose (from charcoal canister) from VSV
(c) Remove the two bolts and VSV from the cylinder head.
(d) Disconnect the two wire clamps from the VSV bracket, and remove the VSV.
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EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) SystemEC±11
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4. INSPECT VSV
A. Inspect VSV for open circuitUsing an ohmmeter, check that there is continuity between
the terminals.
Resistance (Cold): 30±34

If there is no continuity, replace the VSV.
B. Inspect VSV for ground Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV.
C. Inspect VSV operation (a) Check that the air flows with difficulty from ports E to F.
(b) Apply battery voltage across the terminals.
(c) Check that the air flows without resistance from port Eto F.
If operation is not as specified, replace the VSV.
5. REINSTALL VSV (a) Install the VSV with the two bolts.
(b) Connect the two wire clamps to the VSV bracket.
EC±12
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EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) System
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(c) Connect the following hoses:(1) Vacuum hose (from vacuum pipe) to VSV
(2) Vacuum hose (from charcoal canister) to VSV
(d) Connect the VSV connector.
6. REINSTALL INTAKE AIR CONNECTOR (a) Connect the end portions of the intake air connector tothe throttle body and air cleaner hose.
(b) Tighten the two hose clamps.
(c) Install the bolt holding the intake air connector to the cylinder head cover.
(d) Connect the following hoses: (1) Air hose (from ISC valve) to intake air connector
(2) Air hose (from PS air control valve) to intake air con-
nector
7. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
INSPECTION OF CHECK VALVE
1. REMOVE CHECK VALVE(a) Disconnect the grommet on the check valve from thebracket.
(b) Remove the check valve from the hose end on the charcoal canister.
(c) Remove the grommet from the check valve.
2. INSPECT CHECK VALVE (a) Check that air flows from the yellow port to the blackport.
(b) Check that air does not flow from the black port to the yellow port.
If operation is not as specified, replace the check valve.
±
EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) SystemEC±13
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