1991 LEXUS SC400 sensor

(b) Install the exhaust manifold with the eight new nuts.Uniformly tighten the nuts in several passes.
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
(c) Install the main oxygen sensor.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
(d) Install the heat insulator with the three bolts.
3. INSTALL CYLINDER HEADS
A. Place cylinder heads on cylinder block (a) Place two new cylinder head gaskets in position on thecylinder block.
HINT: On the rear side of the cylinder head gasket are
painted marks to distinguish the LH and RH banks, a white
painted mark for the RH bank and a yellow painted mark for
the LH bank.
NOTICE: Be careful of the installation direction.
(b) Place the two cylinder heads in position on the cylinder
head gaskets.
EM±92
±
ENGINE MECHANICAL Cylinder Heads
WhereEverybodyKnowsYourName

B. Install cylinder head boltsHINT:
wThe cylinder head bolts are tighten in two progressive
steps (steps (c) and (e)).
w If any one of the cylinder head bolts broken or deformed,
replace it.
(a) Apply a light coat of engine oil on the threads and under
the heads of the cylinder head bolts.
(b) Te mp o ra rily in sta ll th e twe n ty pla te wa sh e rs an d cylinder head bolts.
(c) Uniformly tighten the ten cylinder head bolts on one side
of the cylinder head in several passes in the sequence
shown, then do the other side as shown.
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
If any one of the bolts does not meet the torque specification,
replace the bolt.
(d) Mark the front of the cylinder head bolt head with paint.
(e) Retighten the cylinder head bolts 90 ° in the numerical
order shown.
(f) Check that the painted mark is now at a 90 ° angle to
front.
4. CONNECT MAIN OXYGEN SENSOR CONNECTORS Connect the RH and LH oxygen sensor connector.
5. INSTALL CIRCULAR PLUGS (a) Place two new circular plugs in position on the cylinderheads, facing the cup side forward.
±
ENGINE MECHANICAL Cylinder HeadsEM±93
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19. INSTALL REAR WATER BY±PASS JOINT(a) Install two new gaskets and the water by±pass joint with
the four nuts. Alternately tighten the nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(b) Install the bolt holding the water by±pass pipe to the
engine hanger.
20. INSTALL FRONT WATER BY±PASS JOINT (a) Install two new gaskets and the water by±pass joint with
the four nuts. Alternately tighten the nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(b) Install the engine wire clamp with the bolt.
(c) Connect the following connectors:
(1) Water temperature sensor connector
(2) Cold start injector time switch connector
(3) Water temperature sender gauge connector
21. INSTALL INTAKE MANIFOLD (a) Place two new gaskets on the cylinder heads with thewhite painted mark facing upward.
NOTICE: Align the port holes of the gasket and cylinder
head. Be careful of the installation direction.
(b) Place the intake manifold in position on the cylinder head with the arrow mark facing forward.
NOTICE: Be careful of the installation direction.
(c) Install and uniformly tighten the six mounting bolts and
four mounting nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolts 30 mm (1.18 in.) in length.
EM±104
±
ENGINE MECHANICAL Cylinder Heads
WhereEverybodyKnowsYourName

31. INSTALL ACCELERATOR BRACKETInstall the bracket with the bolt and stud bolt.
32. INSTALL BRAKE BOOSTER UNION Install the union with two new gaskets and the union bolt.
Torque: 29 N Vm (300 kgf Vcm, 22 ft Vlbf)
33. CONNECT VACUUM HOSES
Connect the following hoses:(1) Vacuum hose to brake booster union
(2) Vacuum hose (from VSV for heater water valve) to
air intake chamber
34. INSTALL THROTTLE BODY (a) Connect the following hoses:(1) Water by±pass hose to throttle body
(2) PCV hose to throttle body
(b) Install a new gasket and throttle body with the two bolts and two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolts 40 mm (1.57 in.) in length.
(c) Install the water by±pass pipe (from rear water bypass
joint) to the clamp on the engine wire cover.
(d) Connect the following connectors: (1) Throttle position sensor connector
(2) (w/ TRAC) Sub±throttle position sensor connector
(3) (w/ TRAC) Sub±throttle actuator connector
±
ENGINE MECHANICAL Cylinder HeadsEM±109
WhereEverybodyKnowsYourName

35. INSTALL HEATER WATER VALVE(a) Install the water valve and bracket assembly with thetwo bolts.
(b) Install the engine wire clamp with the bolt.
(c) Connect the VSV connector.
36. INSTALL ISC VALVE (a) Install a new gasket and the ISC valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(b) Connect the water by±pass hose (from throttle body) to
the ISC valve.
(c) Connect the ISC valve connector.
37. INSTALL EGR VALVE ADAPTOR (a) Install a new gasket, the adaptor and connector bracket(USA spec. only) with the two bolts and two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolts 20 mm (1.79 in.) in length.
NOTICE: Do not touch the air intake chamber and adap-
tor surfaces of the gasket with your hand.
(b) Connect the PCV hose to cylinder head.
(c) (USA Spec. only)
Connect the EGR gas temperature sensor connector.
EM±110
±
ENGINE MECHANICAL Cylinder Heads
WhereEverybodyKnowsYourName

PREPARATION FOR DISASSEMBLY
(See Components on pages EM±74 and 75)1. (M/T) REMOVE FLYWHEEL
2. (A/T) REMOVE DRIVE PLATE
Remove the eight bolts, two spacers and drive plate.
3. INSTALL ENGINE TO ENGINE STAND FOR DISASSEMBLY
4. REMOVE GENERATOR
5. REMOVE THROTTLE BODY WITH INTAKE AIR CONNECTOR (See pages EM±10 to 11)
6. REMOVE TIMING BELT AND PULLEYS (See pages EM±24 to 26)
7. REMOVE WATER PUMP AND BY±PASS HOSE
8. REMOVE FUEL PRESSURE PULSATION DAMPER
9. REMOVE CYLINDER HEAD (See pages EM±36 to 40)
10. REMOVE FUEL PIPE SUPPORT
11. REMOVE OIL PRESSURE SWITCH AND KNOCK SENSORS
SST 09816±30010
12. REMOVE LH ENGINE MOUNTING BRACKET
13. REMOVE RH ENGINE MOUNTING BRACKET
14. REMOVE OIL FILTER BRACKET (a) Remove the union bolt and oil filter bracket.
(b) Remove the gasket from the union bolt.
(c) Remove the O±ring from the oil filter bracket.
15. REMOVE OIL PUMP (See page LU±10)
EM±76
±
ENGINE MECHANICAL Cylinder Block
WhereEverybodyKnowsYourName

5. INSTALL KNOCK SENSORS AND OIL PRESSURESWITCH
Using SST, install the two knock sensors and oil pressure
switch.
SST 09816±30010
Torque:
Knock sensor 44 N Vm
(450 kgf Vcm, 33 ft Vlbf)
Oil pressure switch 14 N Vm
(150 kgf Vcm, 11 ft Vlbf)
6. INSTALL FUEL PIPE SUPPORT
Torque: 14 N Vm (145 kgf Vcm, 10 ft Vlbf)
7. INSTALL CYLINDER HEAD
(See pages EM±54 to 57)
Torque: 1st 34 N Vm (350 kgf Vcm, 25 ft Vlbf)
2nd turn 90 5
3rd turn 90 5
8. INSTALL FUEL PRESSURE PULSATION DAMPER
(See step 1 on page FI±36)
Torque: 41 N Vm (420 kgf Vcm, 30 ft Vlbf)
35 N Vm (350 kgf Vcm, 25 ft Vlbf) for SST
9. INSTALL WATER PUMP AND BY±PASS PIPE
(a) Install the water pump. (See page CO±7)
(b) Install the No. 2 water by±pass pipe with the bolt.
(c) Connect the No. 2 water by±pass hose to the engine hanger.
10. INSTALL THROTTLE BODY WITH INTAKE AIR
CONNECTOR
(See page EM±18)
Torque: 21 N Vm (210 kgf Vcm, 15 ft Vlbf)
11. INSTALL TIMING PULLEYS AND BELT
(See pages EM±29 to 33)
12. INSTALL GENERATOR
Torque: 37 N Vm (380 kgf Vcm, 27 ft Vlbf)
13. REMOVE ENGINE STAND FROM ENGINE
±
ENGINE MECHANICAL Cylinder BlockEM±101
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SERVICE DATA (Cont'd)
TORQUE SPECIFICATIONS
\
\
Part tightened  NVm kgf Vcm ft Vlbf
\
\
Camshaft bearing cap X Cylinder head  20 200 14
\
No.1 cylinder head cover X Cylinder head5.45548 in. Vlbf\
\
No.2 cylinder head cover X Cylinder head  5.4 55 48 in. Vlbf\
\
Intake air connector X Air intake chamber  21 210 15\
\
Throttle body bracket X Throttle body  21 210 15\
\
Throttle body bracket X Cylinder head  21 210 15
\
\
EGR pipe X Intake manifold  21 210 15
\
\
EGR pipe X EGR valve  64 650 47
\
\
Spark plug X Cylinder head  18 180 13
\
\
Throttle body X Intake air connector  21 210 15
\
\
Idler pulley X Oil pump  34 350 25
\
Crankshaft pulley X Crankshaft3243,300239\
\
Camshaft timing pulley X Camshaft  79 810 59\
\
Timing belt tensioner X Oil pump  26 270 20\
\
Drive belt tensioner X Cylinder head  21 210 15\
\
EGR cooler X Cylinder head  14 140 10
\


\
Engine coolant temperature sensor X Cylinder
head 


 


20 


200 


14
\


\
Engine coolant temperature sender gauge X Cylin-
der head 


 


20 


200 


14
\
\
Engine hanger X Cylinder head  39 400 29
\
Cylinder head X Cylinder block1st3435025\
\
 2nd Turn 90
5  
\
\
 3rd Turn 905  
\
\
No.4 Timing belt cover X Cylinder head  8.8 90 78 in.Vlbf\
\
Intake manifold X Cylinder head  21 210 15
\
\
Intake manifold stay X Intake manifold  39 400 29
\
\
Intake manifold stay X Cylinder head  39 400 29
\
\
No.1 fuel pipe X Intake manifold  8.8 90 78 in. Vlbf
\
\
No.2 fuel pipe X Intake manifold  8.8 90 78 in. Vlbf
\
\
Delivery pipe X Intake manifold  21 210 15
\
\
Air intake chamber X Intake manifold  21 210 15
\
Air intake chamber stay X Air intake chamber1818513\
\
Air intake chamber stay X Cylinder head  18 185 13\
\
Vacuum control valve set X Intake manifold  21 210 15\
\
No.2 vacuum pipe X Air intake chamber  21 210 15\
\
Water outlet X Cylinder head  21 210 15
\
\
Water by±pass outlet X Cylinder head  8.8 90 78 in. Vlbf
\
\
Exhaust manifold X Cylinder head  39 400 29
\
\
Exhaust manifold heat insulator X Exhaust manifold  18 185 13
EM±116±
ENGINE MECHANICAL Service Specifications
WhereEverybodyKnowsYourName