1991 LEXUS SC400 Throttle Position

16. REMOVE HEATER WATER VALVE FROM BODY
(a) Disconnect the VSV connector.
(b) Disconnect the bolt holding the engine wire clamp to thewater valve bracket.
(c) Remove the 2 bolts, and disconnect the water valve and bracket assembly.
17. REMOVE THROTTLE BODY
(a) Disconnect the following connectors: (1) Throttle position sensor connector
(2) w/ TRAC:
Sub±throttle position sensor connector
(3) w/ TRAC: Sub±throttle actuator connector
(b) Remove the 2 bolts and 2 nuts, and disconnect the throttle body from the air intake chamber.
(c) Disconnect the following hoses, and remove the throttle body:
(1) PCV hose from throttle body
(2) Water bypass hose from throttle body
(d) Remove the throttle body gasket.
18. REMOVE AIR INTAKE CHAMBER
(a) Disconnect the following hoses: (1) Brake booster vacuum hose from union on air intake
chamber
(2) Vacuum hose (from VSV for heater water valve) from air
intake chamber
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(l) Install the accelerator bracket with the bolt and stud bolt.
(m) Install 2 new gaskets and union with the union bolt.
Torque: 29 NVm (300 kgf Vcm, 22 ft Vlbf)
(n) Connect the following hoses:
(1) Brake booster vacuum hose to union on air intake cham-
ber
(2) Vacuum hose (from VSV for heater water valve to air in-
take chamber
29. INSTALL THROTTLE BODY
(a) Disconnect the following hoses: (1) PCV hose to throttle body
(2) Water bypass hose to throttle body
(b) Install a new gasket and throttle body with the 2 bolts and 2 nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT: Use bolt 40 mm (1.57 in.) in length.
(c) Install the water bypass pipe (from the rear 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
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6. REMOVE THROTTLE BODY WITH INTAKE AIRCONNECTOR
(a) Disconnect the following hoses and connectors:(1) PCV hose
(2) Three vacuum hoses
(3) VSV (for EGR) connector
(4) Throttle position sensor connector
(5) IAC valve connector
(6) (w/ TRAC)
Sub±throttle position sensor connector
(7) (w/ TRAC) Sub±throttle actuator connector
(8) (USA spec. only)
EGR gas temperature sensor connector
(b) Remove the four bolts and two nuts holding the intake air connector to the intake chamber.
(c) Remove the VSV nut.
(d) Disc onnect the two water by±pass hoses from the
throttle body. Plug the hose ends.
(e) Remove the throttle body with the intake air connector and gasket.
7. REMOVE NO. 3 TIMING BELT COVER AND CYLINDER
HEAD REAR COVER
(a) Remove the oil filler cap.
(b) Using a 5 mm hexagon wrench, remove the ten bolts,No. 3 timing belt cover and cylinder head rear cover.
8. DISCONNECT HIGH±TENSION CORDS FROM SPARK PLUGS
(a) Remove the bolt holding the cord clamp from thecylinder head.
(b) Disconnect the two high±tension cord clamps from the No. 3 cylinder head cover.
(c) Disconnect the high±tension cords at the rubber boot. Do not pull on the cords.
NOTICE: Pulling on or bending the cords may damage
the conductor inside.
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16. REINSTALL THROTTLE BODY WITH INTAKE AIRCONNECTOR
(a) Place a new gasket so the protrusion face the intakechamber, and set the throttle body with intake air
connector.
(b) Connect the two water by±pass hoses to the throttle body.
(c) Install the VSV nut.
(d) Install the air intake connector with the four bolts and two
nuts.
Torque: 21 N Vm (210 kgf Vcm, 15 ft Vlbf)
(e) Connect the following hoses and connectors:
(1) PCV hose
(2) Three vacuum hoses
(3) VSV (for EGR) connector
(4) Throttle position sensor connector
(5) IAC valve connector
(6) (w/ TRAC) Sub±throttle position sensor connector
(7) (w/ TRAC) Sub±throttle actuator connector
(8) (USA spec. only) EGR gas temperature sensor connector
17. REINSTALL THROTTLE BODY BRACKET Install the throttle body bracket with the four nuts.
Torque: 21 N Vm (210 kgf Vcm, 15 ft Vlbf)
18. REINSTALL EGR PIPE
(a) Install a new gasket and the EGR pipe with the two bolts.
Torque: 21 N Vm (210 kgf Vcm, 15 ft Vlbf)
(b) Tighten the union nut.
Torque: 64 N Vm (650 kgf Vcm, 47 ft Vlbf)
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INSPECTION AND ADJUSTMENT OF
VALVE CLEARANCE
HINT: Inspect and adjust the valve clearance when the
engine is cold.
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OF BATTERY
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. DRAIN ENGINE COOLANT (See page CO±6)
3. REMOVE THROTTLE BODY COVER (a) Remove the mounting cap nut.
(b) Loosen the two bolts, and remove the throttle body
cover.
4. DISCONNECT CONTROL CABLES FROM THROTTLE BODY
Disconnect the following cables:(1) Accelerator cable
(2) A/T throttle control cable
(3) (w/ Cruise Control System) Cruise control actuator cable
5. REMOVE INTAKE AIR CONNECTOR (a) Disconnect the following hoses:(1) Air hose from ISC valve
(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 throttle body.
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11. DISCONNECT FUEL INLET HOSE FROM LH DELIVERYPIPE
Remove the pulsation damper and two gaskets, and discon-
nect the inlet hose.
12. D I S C O N N E C T F U E L R E T U R N H O S E F R O M F U E L RETURN PIPE
13. DISCONNECT PCV HOSE FROM LH CYLINDER HEAD
14. REMOVE LH NO.3 TIMING BELT COVER (a) Remove the four mounting bolts.
(b) Disconnect the cord grommet from the timing belt cover,
and remove the timing belt cover.
(c) Remove the cord grommet from the high±tension cord.
15. DISCONNECT HEATER WATER VALVE FROM BODY (a) Disconnect the VSV connector.
(b) Remove the bolt holding the engine wire clamp to thewater valve bracket.
(c) Remove the two bolts, and disconnect the water valve and bracket assembly.
16. REMOVE THROTTLE BODY (a) Disconnect the following connectors:(1) Throttle position sensor connector
(2) (w/ TRAC)
Sub±throttle position sensor connector
(3) (w/ TRAC) Sub±throttle actuator connector
(b) Disconnect the following hoses: (1) Water by±pass hose from ISC valve
(2) (USA Spec.) Vacuum hose from throttle body
(3) (Exc. USA Spec.) Three vacuum hoses from throttle body
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(b) Install a new gasket and throttle body with the two boltsand 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 by±pass
joint) to the clamp on the engine wire cover.
(d) Connect the following hoses: (1) Water by±pass hose to the ISC valve
(2) (USA Spec.) Vacuum hose to throttle body
(3) (Exc. USA Spec.) Three vacuum hoses to throttle body
(e) Connect the following connectors: (1) Throttle position sensor connector
(2) (w/ TRAC) Sub±throttle position sensor connector
(3) (w/ TRAC) Sub±throttle actuator
27. REINSTALL 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.
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35. REINSTALL LH ENGINE WIRE COVER(a) Connect portions A and B engine wire cover to the wirebrackets.
(b) Set the VSV (for fuel pressure control system) wire in
original position.
(c) Fit portions C and D of the engine wire cover, matching them with the lower high±tension cord cover and No.3
timing belt cover.
(d) Install the engine wire cover with the two bolts.
36. REINSTALL UPPER HIGH±TENSION CORD COVER (a) Fit portion A of the upper high±tension cover, matchingthe top of the lower high±tension cord cover.
(b) Push the front side of the upper high±tension cord cover, and connect the front side claw groove of the
upper high±tension cord cover to the claw of the lower
high±tension cord cover.
(c) Install the upper high±tension cord cover with the two bolts.
37. 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 to ISC to ISC valve
(2) Air hose (from PS air control valve) to intake air connector
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