LEXUS SC400 1991 Service Repair Manual

TORQUE SPECIFICATIONS
Part tightenedNVmkgf Vcmft Vlbf
Engine drain plug X Cylinder block1818013
Coolant filler plug X Water inlet housing44450 33
Water pump X Cylinder block18185 13
Water inlet housing X Water pump18185 13
Water inlet X Water inlet housing18185 13
Radiator fan shroud X Radiator4.950 43 in. Vlbf
Radiator X Body12120 9
Cooling fan reservoir tank X Radiator fan shroud4.950 43 in. Vlbf
Cooling fan inlet pipe X Radiator fan shroud4.950 43 in. Vlbf
Cooling fan pressure hose X Hydraulic motor64650 47
Radiator reservoir tank X Upper radiator support4.950 43 in. Vlbf
Radiator reservoir tank X Radiator reservoir tank support4.950 43 in. Vlbf
Hydraulic pump rear housing X End plug (for spool valve)19200 14
Hydraulic pump front housing X Rear housing21210 15
Hydraulic pump pulley X Drive shaft59600 43
Solenoid valve X Hydraulic pump rear housing39400 28
Hydraulic pump suction port union X Rear housing13135 10
 Hydraulic pump X Cylinder block 12 mm head 16 160 12
  14 mm head 20 310 22
\
 \
Cooling fan pressure hose X Hydraulic pump 64 650 47
\
 \
RH No.2 timing belt cover X Cylinder block 16 160 12
\
 \
Drive belt idler pulley X Hydraulic pump 37 380 27
\
 \
A/C compressor X Hydraulic pump 49 500 36
\
 \
A/C compressor X Cylinder block 49 500 36\
 \
A/C compressor stay X Oil filter bracket 29 300 22\
 \
Hydraulic motor cover X Motor housing 28 290 21\
 
\

\
Hydraulic motor X Radiator fan shroud
 

4.9
 

50
 

43 in.
Vlbf
\
 \
Cooling fan X Hydraulic motor 15 150 11
\
 \
Cooling fan oil cooler X Body 18 180 13
\
 \
Water temperature sensor X Radiator 7.4 75 65 in. Vlbf
±
COOLIING SYSTEM Service SpecificationsCO±65
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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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COMPONENTS LAYOUT (Cont'd)
±
EMISSION CONTROL SYSTEMS DescriptionEC±3
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SCHEMATIC DRAWING
EC±4±
EMISSION CONTROL SYSTEMS Description
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PREPARATION
SST (SPECIAL SERVICE TOOL)
RECOMMENDED TOOLS
EQUIPMENT
Part NameNote
Engine tune±up testerEngine speed
±
EMISSION CONTROL SYSTEMS PreparationEC±5
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POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM
DESCRIPTION
To reduce HC emission, crankcase blow±by gas (HC) is routed through the PCV valve to the air intake cham-
ber for combustion in the cylinders.
OPERATION
EC±6±
EMISSION CONTROL SYSTEMS Positive Crankcase Ventilation (PVC) System
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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.
±
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.
±
EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) SystemEC±9
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