engine LEXUS SC400 1991 Service Repair Manual

(c) Remove the two bolts and gaskets, and disconnect theEGR pipe from the air intake chamber.
(d) Remove the four mounting bolts, eight mounting nuts and following parts:
(1) VSV for fuel pressure control system
(2) (Exc. USA Spec.)
VSV for EGR system
(3) A/T throttle cable bracket
(e) Disconnect the check (ºDIAGNOSISº) connector from
the intake chamber.
(f) Remove the air intake chamber and four gaskets.
(g) Remove the three bolts, the cold start injector, tube, lead
wire assembly and gasket.
21. DISCONNECT HEATER WATER HOSES Disconnect the following hoses:(1) Water hose from water by±pass pipe
(2) Water hose from rear water by±pass joint
22. DISCONNECT FUEL INLET HOSE FROM LH DELIVERY PIPE
Remove the pulsation damper and two gaskets, and discon-
nect the inlet hose.
23. 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
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24. DISCONNECT EGR PIPE FROM RH CYLINDER HEADRemove the bolt holding the EGR pipe to the RH cylinder
head, and disconnect the EGR pipe.
25. DISCONNECT ENGINE WIRE FROM INTAKE MANIFOLD Remove the two bolts, and disconnect the engine wire.
26. DISCONNECT ENGINE WIRE FROM DELIVERY PIPES, REAR WATER BY±PASS JOINT AND RH CYLINDER
HEAD
(a) Remove the four bolts holding the engine wire to thedelivery pipes, and disconnect the engine wire from the
delivery pipes.
(b) Remove the two bolts holding the engine wire to the rear
water by±pass joint, and disconnect the engine wire
from the rear water by±pass joint.
(c) Remove the two bolts holding the engine wire to the rear
side of the RH cylinder head, and disconnect the engine
wire from the engine wire RH cylinder head.
(d) Disconnect the two engine wire connectors from the connector bracket on the front side of the LH delivery
pipe.
(e) Disconnect the eight injector connectors.
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27. REMOVE FUEL RETURN PIPE(a) Remove the bolt holding the fuel return pipe to the rearside of the LH cylinder head.
(b) Remove the union bolt, two gaskets and return pipe.
28. REMOVE DELIVERY PIPES AND INJECTORS (a) Remove the four nuts holding the delivery pipe to theintake manifold.
(b) Remove the connector bracket, the two delivery pipes, eight injectors assembly, four spacers and eight
insulators.
NOTICE: Be careful not to drop the injectors.
(c) Remove the eight injectors from the delivery pipes.
(d) Remove the O±ring and grommet from each injector.
29. REMOVE INTAKE MANIFOLD Remove the six bolts, four nuts, intake manifold and two gas-
kets.
30. REMOVE FRONT WATER BY±PASS JOINT (a) Disconnect the following connectors:(1) Water temperature sensor connector
(2) Cold start injector time switch connector
(3) Water temperature sender gauge connector
(b) Remove the bolt, and disconnect the engine wire clamp from the water by±pass joint.
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(c) Remove the four nuts, water by±pass joint and twogaskets.
31. REMOVE REAR WATER BY±PASS JOINT (a) Remove the bolt holding the water by±pass pipe to theengine hanger.
(b) Remove the four nuts, water by±pass joint and two gaskets.
32. REMOVE OIL DIPSTICK AND GUIDE FOR ENGINE (a) Remove the mounting bolt.
(b) Pull out the dipstick guide together with the dipstick.
(c) Remove the O±ring from the dipstick guide.
33. REMOVE OIL DIPSTICK AND GUIDE FOR A/T
34. REMOVE EGR PIPE (a) Remove the two nuts holding the EGR pipe to the RHexhaust pipe.
(b) Remove the EGR pipe and gasket.
35. DISCONNECT GROUND STRAP FROM RH CYLINDER HEAD
36. DISCONNECT ENGINE WIRE FROM RH CYLINDER HEAD
Remove the two bolts, and disconnect the engine wire.
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37. DISCONNECT ENGINE WIRE FROM LH CYLINDER HEAD
Remove the five bolts, and disconnect the engine wire.
38. REMOVE ENGINE HANGERS Remove the two bolts and engine hanger. Remove the two
engine hangers.
39. REMOVE CYLINDER HEAD COVERS Remove the eight bolts, seal washers, cylinder head cover
and gasket. Remove the two cylinder head covers.
40. IF NECESSARY, REMOVE SEMI±CIRCULAR PLUGS
41. REMOVE CAMSHAFTS NOTICE: Since the thrust clearance of the camshaft is
small, the camshaft must be held level while it is being
removed. If the camshaft is not kept level, the portion of
the cylinder head receiving the shaft thrust may crack or
be damaged, causing due the camshaft to seize or break.
To avoid this, the following steps should be carried out.
A. Remove exhaust camshaft from RH cylinder head
(a) Bring the service bolt hole of the driven s ub±gear
upward by turning the hexagon wrench head portion of
the exhaust camshaft with a wrench.
(b) Secure the exhaust camshaft sub±gear to the driven
gear with a service bolt.
Recommended service bolt: Thread diameter 6 mm
Thread pitch 1.0 mm
Bolt length 16±20 mm (0.63±0.79 in.)
HINT: When removing the camshaft, make certain that the
torsional spring force of the sub±gear has been eliminated by
the above operation.
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(c) Set the timing mark (one dot mark) of the camshaftdriven gear at approx. 105 angle by turning the hexagon
wrench head portion of the exhaust camshaft with a
wrench.
(d) Alternately loosen and remove the two bearing cap bolts
holding the intake camshaft side of the oil feed pipe to
the cylinder head.
(e) Uniformly loosen and remove the eight bearing cap bolts in several passes in the sequence shown.
(f) Re mo ve th e oil fe e d pip e , fo u r be a rin g ca p s an d
exhaust camshaft.
B. Remove intake camshaft from RH cylinder head (a) Remove the rear bearing cap.
(b) Set the timing mark ( one dot mark) of the camshaft drive
gear at approx. 455 angle by turning the hexagon
wrench head portion of the intake camshaft with a
wrench.
(c) Uniformly loosen and remove the eight bearing cap bolts in several passes in the sequence shown.
(d) Remove the four bearing caps, oil seal and intake
camshaft.
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C. Remove exhaust camshaft from LH cylinder head(a) Bring the service bolt hole of the driven s ub±gear
upward by turning the hexagon wrench head portion of
the exhaust camshaft with a wrench.
(b) Secure the exhaust camshaft sub±gear to the driven gear with a service bolt.
Recommended service bolt: Thread diameter 6 mm
Thread pitch 1.0 mm
Bolt length 16±20 mm (0.63±0.79 in.)
HINT: When removing the camshaft, make certain that the
torsional spring force of the sub±gear has been eliminated by
the above operation.
(c) Set the timing mark (two dot marks) of the camshaft
driven gear at approx. 155 angle by turning the hexagon
wrench head portion of the exhaust camshaft with a
wrench.
(d) Alternately loosen and remove the two bearing cap bolts
holding the intake camshaft side of the oil feed pipe to
the cylinder head.
(e) Uniformly loosen and remove the eight bearing cap bolts in several passes in the sequence shown.
(f) Re mo ve th e oil fe e d pip e , fo u r be a rin g ca p s an d
exhaust camshaft.
D. Remove intake camshaft from LH cylinder head (a) Remove the front bearing cap.
(b) Set the timing mark ( one dot mark) of the camshaft drive
gear at approx. 605 angle by turning the hexagon
wrench head portion of the intake camshaft with a
wrench.
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(c) Uniformly loosen and remove the eight bearing capbolts in several passes in the sequence shown.
(d) Remove the four bearing caps, oil seal and intake camshaft.
HINT: Arrange the bearing caps in correct order.
42. DISASSEMBLE EXHAUST CAMSHAFTS (a) M ount the hexagon wrench head portion of the
camshaft in a vise.
NOTICE: Be careful not to damage the camshaft.
(b) Insert a service bolt (A) into the service hole of the camshaft sub±gear.
(c) Using a screwdriver, turn the sub±gear clockwise, and
remove the service bolt (B).
NOTICE: Be careful not to damage the camshaft.
(d) Using snap ring pliers, remove the snap ring.
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(e) Remove the following parts:(1) Wave washer
(2) Camshaft sub±gear
(3) Camshaft gear spring
HINT: Arrange the camshaft sub±gears and gear springs (RH
side and LH side).
43. REMOVE CIRCULAR PLUGS Remove the two bolts, seal washers, bearing cap and circular
plug. Remove the two circular plugs.
HINT: Arrange the bearing caps (RH side and LH side).
44. DISCONNECT MAIN OXYGEN SENSOR CONNECTORS Disconnect the RH and LH oxygen sensor connector.
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45. REMOVE CYLINDER HEADS(a) Uniformly loosen the ten cylinder head bolts on one side
of each cylinder head in several passes in the sequence
shown, then do the other side as shown. Remove the
twenty cylinder head bolts and plate washers.
NOTICE: Head warpage or cracking could result from re-
moving bolts in an incorrect order.
(b) Lift the cylinder heads from the dowels on the cylinder block, and place the two cylinder heads on wooden
blocks on a bench.
HINT: If the cylinder head is difficult to lift off, pry between the
cylinder head and cylinder block with a screwdriver.
NOTICE: Be careful not to damage the contact surfaces
of the cylinder head and cylinder block.
46. REMOVE EXHAUST MANIFOLD FROM RH CYLINDER HEAD
(a) Remove the three bolts and heat insulator.
(b) Remove the main oxygen sensor.
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