LEXUS SC400 1991 Service Repair Manual

COMPONENTS FOR REMOVAL AND INSTALLATION OF EGR VALVE
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±21
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INSPECTION OF EGR VALVE
(USA Spec.)
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. DISCONNECT EGR VALVE CONNECTOR
3. INSPECT EGR VALVE RESISTANCE Using an ohmmeter, measure the resistance between termi-
nal B1 (or B2) and other terminals (S1, S2, S3 and S4).
Resistance (Cold): 19.9±23.4

4. DRAIN ENGINE COOLANT (See page CO±6)
5. REMOVE EGR VALVE (a) Disconnect the following hoses:(1) Water by±pass hose (from ISC valve) from the EGR
valve
(2) Water by±pass hose (from rear water by±pass joint) from the EGR valve
(b) Remove the two nuts, EGR valve and gasket.
6. INSPECT EGR VALVE
A. Visually inspect EGR valve Check for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
EC±22
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EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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B. Inspect EGR valve operation(a) Remove the three bolts and stepping motor from thehousing.
(b) Apply battery voltage to terminal B1 (or B2), and while repeately grounding (*S4)±(S4 and *S3)±(S3 and
*S2)±(S2 and *S1)±(S1 and *S4) in sequence, check
that the valve moves toward the open position.
HINT: Keep the terminal marked with an asterisk (*) grounded
while proceeding to the next grounding.
(c) Apply battery voltage to terminal B1 (or B2), and while repeately grounding (*S1)±(S1 and *S2)±(S2 and
*S3)±(S3 and *S4)±(S4 and *S1) in sequence, check
that the valve moves toward the closed position.
HINT:
w Keep the terminal marked with an asterisk (*) grounded
while proceeding to the next grounding.
w Perform this operation after opening the valve by
performing step (b) above.
If operation is not as specified, replace the EGR valve assem-
bly.
(d) Reinstall the stepping motor to the housing with the three bolts.
7. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor. Be careful
of the installation direction.
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±23
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(b) Install the EGR valve with the two nuts.
Torque: 18 NVm (185 kgf Vcm, 13 ft Vlbf)
(c) Connect the following hoses:
(1) Water by±pass hose (from ISC valve) to the EGR valve
(2) Water by±pass hose (from rear water by±pass joint) to the EGR valve
8. RECONNECT EGR VALVE CONNECTOR
9. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
10. REFILL WITH ENGINE COOLANT (See page CO±7)
INSPECTION OF EGR VALVE
(Exc. USA Spec.)
1. DRAIN ENGINE COOLANT (See page CO±6)
2. REMOVE EGR VALVE (a) Disconnect the following hoses:(1) Vacuum hose (from VSV) from EGR valve
(2) Vacuum hose (from VSV) from EGR vacuum
modulator
(3) Vacuum hose (from EGR vacuum modulator) f rom EGR valve
(4) Water by±pass hose (from ISC valve) from the
EGR valve
(5) Water by±pass hose (from rear water by±pass joint) from the EGR valve
(b) Disconnect the vacuum modulator bracket from the
EGR valve.
(c) Remove the two nuts, EGR valve and gasket.
EC±24
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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3. INSPECT EGR VALVECheck for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
4. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor.
Be careful of the installation direction.
(b) Install the EGR valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the vacuum modulator bracket to the EGR valve.
(d) Connect the following hoses:
(1) Vacuum hose (from VSV) to EGR valve
(2) Vacuum hose (from VSV) to EGR vacuum modula- tor
(3) Vacuum hose (from EGR vacuum modulator) to EGR valve
(4) Water by±pass hose (from ISC valve) to the EGR
valve
(5) Water by±pass hose (from rear water by±pass joint) to the EGR valve
5. REFILL WITH ENGINE COOLANT (See page CO±7)
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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THREE±WAY CATALYST (TWC) SYSTEM
DESCRIPTION
To reduce HC, CO and NOx emissions, they are oxidized, reduced and convert\
ed to nitrogen (N), carbon diox-
ide (CO) and water (HO) by the catalyst.
OPERATION
INSPECTION OF EXHAUST PIPE
ASSEMBLY
1. CHECK CONNECTIONS FOR LOOSENSESS ORDAMAGE
2. CHECK CLAMPS FOR WEAKNESS, C RACKS OR
DAMAGE
INSPECTION OF CATALYTIC
CONVERTER
CHECK FOR DENTS OR DAMAGE
If any part of the protector is damaged or dented to the extent
that is contacts the catalyst, repair or replace it.
INSPECTION OF HEAT INSULATOR
1. CHECK HEAT INSULATOR FOR DAMAGE
2. CHECK FOR ADEQUATE CLEARANCE BETWEENCATALYTIC CONVERTER AND HEAR INSULATOR
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EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) SystemEC±17
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COMPONENTS
REPLACEMENT OF CATALYTIC
CONVERTERS
(Front Catalytic Converter)
1. REMOVE CATALYTIC CONVERTER (FRONT)(a) Check that the converter is cool.
(b) Remove the two bolts and nuts holding the catalyticconverters to the front exhaust pipe.
(c) Disconnect the front exhaust pipe from the catalytic converter, and remove the gasket.
(d) Remove the four nuts holding the catalytic converter to the exhaust manifold.
2. REINSTALL CATALYTIC CONVERTER (a) Install a new gasket and the catalytic converter to theexhaust manifold with four new nuts.
Torque: 62 N Vm (630 kgf Vcm, 46 ft Vlbf)
(b) Install a new gasket to front end of the front exhaust
pipe, and torque the front exhaust pipe to the catalytic
converter.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
EC±18±
EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) System
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(Rear Catalytic Converter)
1. (USA Spec.)REMOVE SUB±OXYGEN SENSOR
Remove the two nuts and sub±oxygen sensor from the front
exhaust pipe.
2. REMOVE REAR CATALYTIC CONVERTER (FRONT EXHAUST PIPE)
(a) Remove the two bolts and nuts holding the front exhaust
pipe to the center exhaust pipe.
(b) Remove the two bolts and nuts holding the front exhaust
pipe to the front catalytic converter, and remove the front
exhaust pipe and two gaskets.
3. REINSTALL REAR CATALYTIC CONVERTER (FRONT EXHAUST PIPE)
Install the two new gaskets, the front exhaust pipe with the
four bolts and new nuts.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
4. (USA Spec.)
REINSTALL SUB±OXYGEN SENSOR
Install the new gasket, the sub±oxygen sensor to the front ex-
haust pipe with the two nuts.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
±
EMISSION CONTROL SYSTEMS Three±way Catalyst (TWC) SystemEC±19
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SERVICE SPECIFICATIONS
SERVICE DATA
EG065±0A Tune±up Battery specific gravity  1.27±1.29
    (when fully charged at 205C (68 5F))
  High±tension cord resistance Limit 25 k
per cord
  Valve clearance (Cold) Intake 0.15±0.25 mm (0.006±0.010 in.)
   Exhaust 0.25±0.35 mm (0.010±0.014 in.)
Valve clearance adjusting shimNo.012.500 mm (0.0984 in.)   No.62 2.525 mm (0.0994 in.)   No.63 2.550 mm (0.1004 in.)   No.64 2.575 mm (0.1014 in.)   No.06 2.600 mm (0.1024 in.)
   No.65 2.625 mm (0.1033 in.)
   No.66 2.650 mm (0.1043 in.)
   No.67 2.675 mm (0.1053 in.)
   No.13 2.700 mm (0.1063 in.)
   No.68 2.725 mm (0.1073 in.)
   No.18 2.750 mm (0.1083 in.)
No.192.775 mm (0.1093 in.)   No.23 2.800 mm (0.1102 in.)   No.70 2.825 mm (0.1112 in.)   No.28 2.850 mm (0.1122 in.)   No.71 2.875 mm (0.1132 in.)
   No.33 2.900 mm (0.1142 in.)
   No.72 2.925 mm (0.1152 in.)
   No.38 2.950 mm (0.1161 in.)
   No.73 2.975 mm (0.1171 in.)
   No.43 3.000 mm (0.1181 in.)
No.743.025 mm (0.1191 in.)   No.48 3.050 mm (0.1201 in.)   No.75 3.075 mm (0.1211 in.)   No.51 3.100 mm (0.1220 in.)   No.76 3.125 mm (0.1230 in.)   No.77 3.150 mm (0.1240 in.)
   No.78 3.175 mm (0.1250 in.)
   No.56 3.200 mm (0.1260 in.)
   No.79 3.225 mm (0.1270 in.)
   No.80 3.250 mm (0.1280 in.)
   No.81 3.275 mm (0.1289 in.)
No.613.300 mm (0.1299 in.)  Ignition timing  8 ± 12 5 BTDC @ idle 


 


 


 

(w/ Terminals TE1 and E1 connected
of DLC1)
  Idle speed  700
+ 50 rpm
 Intake at idle speed  60 kPa (450 mmHg. 17.7 in.Hg)
 manifold
 vacuum   
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1UZ ± FE ENGINE ENGINE MECHANICALEG±205
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Compression at 250 rpm STD 1,226 kPa (12.5 kgf/cm2, 178 psi) or
more
 pressureLimit 981 kPa (10.0 kgf/cm2, 142 psi)  Difference of pressure between each cylinder  98 kPa (1.0 kgf/cm2, 14 psi) or less 

Timing belt
tensionerProtrusion from housing end10.5±11.5 mm (0.413±0.453 in.)
 Cylinder head Warpage Limit 0.10 mm (0.039 in.)
  Valve seat  
  Refacing angle  30
5, 45 5, 75 5
  Contacting angle  455
  Contacting width  1.0±1.4 mm (0.039±0.055 in.)
  Cylinder head bolt thread inside diameter STD 9.770±9.960 mm (0.3846±0.3921 in.)
   Limit 9.60 mm (0.3780 in.)
 Valve guideInside diameter6.010±6.030 mm (0.2366±0.2374 in.)
 bushing Outside diameter (for repair part) STD 11.048±11.059 mm (0.4350±0.4354
in.)
 O/S 0.05 11.098±11.109 mm (0.4369±0.4374 in.) ValveValve overall lengthSTD (Intake)94.95 mm (3.7382 in.)   (Exhaust) 96.90 mm (3.8150 in.)   Limit (Intake) 94.45 mm (3.7185 in.)   (Exhaust) 96.40 mm (3.7953 in.)
  Vale face angle  44.55
  Stem diameter Intake 5.970±5.985 mm (0.2350±0.2356 in.)
   Exhaust 5.965±5.980 mm (0.2348±0.2354 in.)
  Stem oil clearance STD (Intake) 0.025±0.060 mm (0.0010±0.0024 in.)
   (Exhaust) 0.030±0.065 mm (0.0012±0.0026 in.)
   Limit (Intake) 0.08 mm (0.0031 in.)
   (Exhaust) 0.10 mm (0.0039 in.)
  Margin thickness STD 1.0 mm (0.039 in.)
   Limit 0.5 mm (0.020 in.)
 Valve spring Squareness Limit 2.0 mm (0.079 in.)
  Free length  43.6 mm (1.717 in.)
  Installed tension at 32.9 mm (1.295 in.)  186±206 N (19.0±21.0 kgf, 41.9±46.3
lbf)
 

Valve lifter 

Lifter diameter 


 

30.966±30.976 mm (1.2191±2.2195
in.)
 


 


Lifter bore diameter 


 


31.000±31.016 mm (1.2205±1.2211
in.)
  Oil clearance STD 0.024±0.050 mm (0.0009±0.0020 in.)
   Limit 0.07 mm (0.0028 in.)
EG±206±
1UZ ± FE ENGINE ENGINE MECHANICAL
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