1991 LEXUS SC400 engine

5. REMOVE RH ENGINE WIRE COVERRemove the bolt and engine wire cover.
6. REMOVE LH ENGINE WIRE COVER Remove the 2 bolts and engine wire cover.
7. REMOVE VSV FOR EVAP SYSTEM Remove the 2 bolts, and disconnect the VSV from the cylin-
der head cover and timing belt cover.
8. REMOVE RH NO.3 TIMING BELT COVER Remove the 3 bolts, timing belt cover and 3 gaskets.
9. REMOVE LH NO.3 TIMING BELT COVER
(a) Remove the 4 bolts
(b) Disconnect the cord grommet from the timing belt cover, and remove the timing belt cover and 3 gaskets.
(c) Remove the cord grommet from the high±tension cord.
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10. DISCONNECT COLD START INJECTOR CONNECTOR
11. DISCONNECT RH CAMSHAFT POSITION SENSORCONNECTOR
(a) Disconnect the connector from the ignition coil bracket.
(b) Disconnect the camshaft position sensor connector.
12. D I S C O N N E C T L H C A M S H A F T P O S I T I O N S E N S O R
CONNECTOR
13. DISCONNECT HIGH±TENSION CORDS FROM SPARK PLUGS
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 con-
ductor inside.
14. REMOVE SPARK PLUGS Using a 16 mm plug wrench, remove the 8 spark plugs.
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15. CHECK CYLINDER COMPRESSION PRESSURE
(a) Reconnect the battery negative (±) cable.
(b) Insert a compression gauge into the spark plug hole.
(c) Fully open the throttle.
(d) Wh ile cra n kin g th e en g in e , me a su re th e co mp re ssio npressure.
HINT: Always use a fully charged battery to obtain engine
speed of 250 rpm or more.
(e) Repeat steps (b) through (d) for each cylinder. NOTICE: This measurement must be done in as short a
time as possible.
Compression pressure:
1,226 kPa (12.5 kgf/cm
2, 178 psi) or more
Minimum pressure: 981 kPa (10.0 kgf/cm
2, 142 psi)
Difference between each cylinder: 98 kPa (1.0 kgf/cm
2, 14 psi) or less
(f) If the cylinder compression in one or more cylinders is low,pour a sm all amount of engine oil into the cylinder through the
spark plug hole and repeat steps (b) through (d) for cylinders
with low compression.
w If adding oil helps the compression, it is likely that the
piston rings and/or cylinder bore are worn or damage.
w If pressure stays low, a valve may be sticking or seating
is improper, or there may be leakage past the gasket.
(g) Disconnect the battery negative (±) cable.
16. REINSTALL SPARK PLUGS
Using a 16 mm plug wrench, install the 8 spark plugs.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
17. R E C O N N E C T H I G H ± T E N S I O N C O R D S TO S PA R K
PLUGS
18. RECONNECT RH CAMSHAFT POSITION SENSOR CONNECTOR
(a) Connect the camshaft position sensor connector.
(b) Install the camshaft position sensor connector to the ignition
coil bracket.
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19. RECONNECT LH CAMSHAFT POSITION SENSORCONNECTOR
20. RECONNECT COLD START INJECTOR CONNECTOR
21. REINSTALL RH NO.3 TIMING BELT COVER
(a) Install the 3 gaskets to the timing belt cover.
(b) Fit the portion A of the timing belt cover, matching it with the lower high±tension cord cover.
(c) Install the timing belt cover with the 3 bolts.
22. REINSTALL VSV FOR EVAP SYSTEM Install the VSV with the 2 bolts.
23. REINSTALL LH NO.3 TIMING BELT COVER
(a) Install the 3 gaskets to the timing belt cover.
(b) Install the cord grommet to the high±tension cord (from the LH ignition coil).
(c) Install the cord grommet to the timing belt cover.
(d) Fit the portion A of the timing belt cover, matching it with the lower high±tension cord cover.
(e) Install the timing belt cover with the 4 bolts.
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24. REINSTALL RH ENGINE WIRE COVER
(a) Fit portions A and B of the engine wire cover, matching themwith the lower high±tension cord cover and No.3 timing belt
cover.
(b) Install the timing belt cover with the bolt.
25. REINSTALL LH ENGINE WIRE COVER
(a) Connect portions A and B of the engine wire cover to the wire
brackets.
(b) Set the VSV (for the fuel pressure) 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 timing belt cover with the 2 bolts.
26. REINSTALL UPPER HIGH±TENSION CORD COVER
(a) Fit portion A of the upper high±tension cord cover matching the top of the lower high±tension cord cover.
(b) Push the front side of the upper high±tension cord cover, and
fit 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 2 bolts.
27. REINSTALL INTAKE AIR CONNECTOR
(a) Connect the end portions of the intake air connector to the throttle body and air cleaner hose.
(b) Tighten the 2 hose clamps.
(c) Install the bolt holding the intake air connector to the cylinder head cover.
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(d) Connect the following hoses:(1) Air hose to IAC valve
(2) Air hose (from air control valve on PS pump) to intake air
connector
28. RECONNECT NEGATIVE TERMINAL CABLE TO BATTERY
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TIMING BELT
EG21Q±01
COMPONENTS FOR REMOVAL AND
INSTALLATION
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