1991 LEXUS SC400 check engine

REMOVAL OF TIMING BELT
(See Components on page EM±23)1. REMOVE WATER PUMP PULLEY AND RADIATOR (See steps 1 to 3, 6 and 7 on pages EM±64 and 66)
2. REMOVE NO. 3 AND NO. 2 TIMING BELT COVERS (a) Remove the oil filler cap.
(b) Using a 5 mm hexagon wrench, remove the nine bolts,No. 3, No. 2 timing belt covers and gasket.
3. REMOVE DRIVE BELT TENSIONER Remove the three bolts and tensioner.
4. SET NO. 1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley and align its groove withtiming mark º0º of the No. 1 timing belt cover.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that the timing marks of the camshaft timing pulleys are aligned with the timing marks of the No. 4
timing belt cover.
If not, turn the crankshaft one revolution (360 5).
5. REMOVE TIMING BELT FROM CAMSHAFT TIMING PULLEYS
HINT: (Re±using timing belt)
Place matchmarks on the timing belt and camshaft timing
pulleys as shown in the illustration.
EM±24
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ENGINE MECHANICAL Timing Belt
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INSPECTION OF TIMING BELT
COMPONENTS
1. INSPECT TIMING BELTNOTICE:w Do not bend, twist or turn the timing belt inside
out.
w Do not allow the timing belt to come into contact
with oil, water or steam.
w Do not make use of timing belt tension when
installing or removing the mount bolt of the
camshaft timing pulley.
If there are any defects as shown in the illustrations, check
the following points:
(a) Premature parting
w Check for proper installation.
w Check the timing cover gasket for damage and
proper installation.
(b) If the belt teeth are cracked or damaged, check to see if either the camshaft or water pump is locked.
(c) If there is noticeable wear or cracks on the belt face, check to see if there are nicks on the side of the idler
pulley lock.
(d) If there is wear or damage on only one side of the belt, check the belt guide and the alignment of each pulley.
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ENGINE MECHANICAL Timing BeltEM±27
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(e) If there is noticeable wear on the belt teeth, check thetiming cover for damage, correct gasket installation and
foreign material on the pulley teeth.
If necessary, replace the timing belt.
2. INSPECT IDLER PULLEY Check the turning smoothness of the idler pulley.
If necessary, replace the idler pulley.
3. INSPECT DRIVE BELT TENSIONER Check the turning smoothness of the tensioner.
If necessary, replace the tensioner.
4. INSPECT TIMING BELT TENSIONER (a) Visually check tensioner for oil leakage.
HINT: It is normal for a tensioner to show a small trance of oil
on the pushrod seal.
However, if there is an outright oil leak, the tensioner must be
replaced.
(b) Hold the tensioner with both hands, and push the push rod firmly against the floor or wall to check that it doesn't
move.
If the push rod moves, replace the tensioner.
EM±28
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ENGINE MECHANICAL Timing Belt
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(c) Measure the protrusion of the push rod from housingend.
Protrusion: 7.7±10.5 mm (0.303±0.413 in.)
If the protrusion is not as specified, replace the tensioner.
INSTALLATION OF TIMING BELT
(See Components page EM±23)1. INSTALL CRANKSHAFT TIMING PULLEY (a) Align the pulley set key with the key groove of the pulley.
(b) Slide on the timing pulley facing the flange side inward.
2. INSTALL IDLER PULLEY (a) Apply adhesive to two or three threads of the pivot bolt.
Adhesive: Part No. 08833±00080, THREE BOND 1344, LOCTITE 242 or equivalent
(b) Using a 10 mm hexagon wrench, install the plate washer
and pulley with the pivot bolt.
Torque: 34 N Vm (350 kgf Vcm, 25 ft Vlbf)
(c) Check that the pulley bracket moves smoothly.
3. TEMPORARILY INSTALL TIMING BELT NOTICE: The engine should be cold.
(a) Use the crankshaft pulley bolt to turn the crankshaft andalign the timing marks on the crankshaft timing pulley
and on the oil pump body.
(b) Remove any oil or water on the crankshaft timing pulley and idler pulley, and keep them clean.
(c) Install the timing belt on the crankshaft timing pulley and
idler pulley.
HINT (When re±using timing belt): Align the matchmarks of
the crankshaft timing pulley and timing belt, and install the
belt with the arrow pointing in the direction of engine revolu-
tion.
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ENGINE MECHANICAL Timing BeltEM±29
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(b) Turn the camshaft, and align the timing marks of thecamshaft timing pulleys and No. 4 timing belt cover.
SST 09278±54012
9. INSTALL TIMING BELT HINT (When re±using timing belt): Align the matchmarks of
the timing belt and camshaft timing pulleys.
(a) Remove any oil or water on the camshaft timing pulley,and keep it clean.
(b) Install the timing belt, checking the tension between the
crankshaft timing pulley and exhaust camshaft timing
pulley.
10. SET TIMING BELT TENSIONER (a) Using a press, slowly press in the push rod using981±9,807N (100±1,000 kgf, 220±2,205 lbf) of
pressure.
(b) Align the holes of the push rod and housing, pass a 1.50
mm hexagon wrench through the holes to keep the push
rod retracted.
(c) Release the press.
(d) Install the dust boot onto the tensioner.
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ENGINE MECHANICAL Timing BeltEM±31
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11. INSTALL TIMING BELT TENSIONER(a) Temporarily install the tensioner with the two bolts.
(b) Alternately tighten the two bolts.
Torque: 26 N Vm (270 kgf Vcm, 20 ft Vlbf)
(c) R e m o v e t h e 1 . 5 0 m m h e x agon wrench from the
tensioner with pliers.
12. CHECK VALVE TIMING (a) Turn the crankshaft pulley two revolutions from TDC toTDC.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that each pulley aligns with the timing marks as shown in the figure.
If the marks do not align, remove the timing belt and reinstall
it.
13. INSTALL DRIVE BELT TENSIONER Install the tensioner with the three bolts.
Torque: 21 N Vm (210 kgf Vcm, 15 ft Vlbf)
NOTICE: Be careful not to drop the bolts inside the timing
belt cover.
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ENGINE MECHANICAL REPAIR INSTRUCTIONS
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14. INSTALL NO. 2 AND NO. 3 TIMING BELT COVERS(a) Install the gasket on the timing belt cover.
(b) Using a 5 mm hexagon wrench, install the belt coverswith the nine bolts.
(c) Install the oil filler cap.
15. INSTALL RADIATOR AND WATER PUMP PULLEY (See steps 15, 16, 19 and 24 on pages EM±110 to 112)
16. FILL ENGINE WITH COOLANT (See page CO±5)
Capacity (w/ Heater):
M/T 8.5 liters (9.0 US qts, 7.5 Imp. qts)
A/T 8.4 liters (8.9 US qts, 7.4 Imp. qts)
17. (A/T)CHECK AUTOMATIC TRANSMISSION FLUID LEVEL
(See page MA±11)
NOTICE: Do not overfill.
18. START ENGINE AND CHECK FOR LEAKS
19. CHECK IGNITION TIMING (See page IG±14)
Ignition timing:
105 BTDC @ idle
(w/ Terminals TE1 and E1 connected)
20. PERFORM ROAD TEST Check for abnormal noise, shock, slippage, correct shift
points and smooth operation.
21. RECHECK ENGINE COOLANT LEVEL
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ENGINE MECHANICAL Timing BeltEM±33
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IDLE AND/OR 2,500 RPM HC/CO
CONCENTRATION CHECK METHOD
HINT: This check is used only to determine whether or not the
idle HC/CO complies with regulations.
1. INTIAL CONDITIONS (a) Engine at normal operating temperature.
(b) Air cleaner installed.
(c) All pipes and hoses of air induction system connected.
(d) All accessories switched OFF.
(e) All vacuum lines properly connected.
HINT: All vacuum hoses for EGR systems, etc. should be
properly connected.
(f) EFI system wiring connectors fully plugged.
(g) Transmission in neutral range.
(h) Tachometer and HC/CO meter calibrated at hand.
2. START ENGINE
3. RACE ENGINE AT 2,500 PRM FOR APPROX. 120 SECONDS
4. INSERT HC/CO METER TESTING PROBE INTO TAILPIPE AT LEAST 40 cm (1.3 ft)
5. CHECK HC/CO CONCENTRATION AT IDLE AND/OR 2,500 PRM
Complete the measuring within three times.
HINT: When performing the 2 mode (2,500 rpm and idle) test,
follow the measurement order prescribed by the regulations.
If the HC/CO concentration at 2,500 rpm does not comply
with regulations, try the following procedure.
Race the engine again at 2,500 rpm for approx. 1 minute and
quickly repeat steps 4 and 5 above.
This may correct the problem.
EM±28
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ENGINE MECHANICAL Idle and/or 2,500 rpm HC/CO
Concentration Check Method
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