check engine LEXUS SC400 1991 Service Repair Manual

3. INSPECT EGR VALVECheck for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
4. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor.
Be careful of the installation direction.
(b) Install the EGR valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the vacuum modulator bracket to the EGR valve.
(d) Connect the following hoses:
(1) Vacuum hose (from VSV) to EGR valve
(2) Vacuum hose (from VSV) to EGR vacuum modula- tor
(3) Vacuum hose (from EGR vacuum modulator) to EGR valve
(4) Water by±pass hose (from ISC valve) to the EGR
valve
(5) Water by±pass hose (from rear water by±pass joint) to the EGR valve
5. REFILL WITH ENGINE COOLANT (See page CO±7)
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EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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TUNE±UP
EG10Z±05
ENGINE COOLANT INSPECTION
1. CHECK ENGINE COOLANT LEVEL AT RESERVOIR TANK
The coolant level should be above the ªCOLD LEVELº at nor-
mal temperature (20 5C (68 5F)).
If low, check for leaks and add coolant up to the ªCOLD LEV-
ELº
2. CHECK ENGINE COOLANT QUALITY
(a) Remove the radiator cap from the reservoir tank.
CAUTION: To avoid the danger of being burned, do not remove
it while the engine and radiator are still hot as fluid and steam
can be blown out under pressure
(b) There should not be any excessive deposits of rust or scale around the radiator cap or reservoir tank filler hole, and the
coolant should be free from oil.
If excessively dirty, clean the coolant passages and replace
the coolant.
Capacity (w/ Heater):
10.8 liters (11.4 US qts, 9.5 lmp. qts)
HINT:
wUse a good brand of ethylene±glycol base coolant and
mix it according to the manufacturer's directions.
w Using coolant which includes more than 50%
ethylene±glycol(but not more than 70%) is
recommended.
NOTICE:
w Do not use a alcohol type coolant.
w The coolant should be mixed with demineralized water or
distilled water.
(c) Reinstall the radiator cap.
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1UZ±FE ENGINE ENGINE MECHANICALEG±9
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EG0B4±0K
ENGINE OIL INSPECTION
1. CHECK OIL QUALITYCheck the oil for deterioration, entry of water, discoloring or
thinning.
If oil quality is visibly poor, replace the oil.
Oil grade:
API grade SG or SH, Energy±Conserving II or ILSAC
multigrade engine oil. Recommended viscosity is as
shown in the illustration, with SAE 5W±30 being the
preferred engine oil.
Drain and refill capacity: w/ Oil filter change
4.8 liters (5.1 US qts, 4.2 lmp. qts)
w/o Oil filter change
4.5 liters (4.8 US qts, 4.0 lmp. qts)
2. CHECK ENGINE OIL LEVELThe oil level should be between the ªLº and ªFº marks on the
dipstick.
If low, check for leakage and add oil up to the ªFº mark.
EG3E2±01
BATTERY INSPECTION
1. CHECK BATTERY ELECTROYTE LEVEL AND VOLTAGE
(a) Check the electrolyte quantity of each cell.If under the lower level, replace the battery (or add distilled
water if possible.). Need to check the charging system.
(b) Measure the battery voltage between the terminals negative (±) and positive (+) of the battery.
Standard voltage:
12.7±12.9 V at 20 5C (68 5F)
HINT:
w Before measuring the voltage, turn the ignition switch
OFF and turn off the electrical systems (headlight,
blower motor, rear defogger etc.) for 60 seconds to
remove the surface charge.
EG±10
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wIf the vehicle has been running, wait 5 minutes or more
after the vehicle stops before measuring the battery
voltage.
If the voltage is less than specification, charge the battery.
HINT: Check the indicator as shown in the illustration.
1. C H E C K B AT T E RY S P E C I F I C G R AV I T Y A N D ELECTROLYTE LEVEL
2. CHECK BATTERY TERMINALS AND FUSES
(a) Check that the battery terminals are not loose or corroded.
(b) Check the fuses for continuity.
EG3F9±01
AIR FILTER INSPECTION AND
CLEANING
1. REMOVE AIR FILTER
(a) Open the air cleaner cap.
(b) Remove the air filter.
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1UZ±FE ENGINE ENGINE MECHANICALEG±11
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2. INSPECT AND CLEAN AIR FILTER
(a) Visually check that the air filter is not excessively damagedor only.
If necessary, replace the air filter.
(b) Clean the air filter with compressed air. First blow from the inside thoroughly, then blow off the out-
side of the air filter.
3. REINSTALL AIR FILTER
EG1KB±02
HIGH±TENSION CORDS INSPECTION
1. REMOVE NO.3 TIMING BELT COVERS (See steps 10 to 14 on pages EG±16)
2. REMOVE HIGH±TENSION CORDS (See step 1 on page IG±16)
NOTICE: Pulling on or bending the cords may damage the con-
ductor inside.
3. INSPECT HIGH±TENSION CORD RESISTANCE Using an ohmmeter, measure the resistance.
Maximum resistance:
25 k
per cord
If the resistance is greater than maximum, replace the cord.
4. REINSTALL HIGT±TENSION CORDS (See step 1 on page IG±19)
5. REINSTALL NO.3 TIMING BELT COVERS (See steps 28 to 30 on pages EG±29)
EG±12
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EG0EY±02
DRIVE BELT INSPECTION
INSPECT DRIVE BELT
HINT: A belt tensioner is used, so checking the belt tension
is not necessary.
(a) Visually check the belt for excessive wear, frayed cords etc. If necessary, replace the drive belt.
HINT:
wCracks on the rib side of a belt are considered
acceptable. If the drive belt has chunks missing from the
ribs, it should be replaced.
w The drive belt tension can be released by turning the the
belt tensioner counterclockwise. The pulley bolt for the
belt tensioner has a left±hand thread.
(b) Check the belt tensioner operation. wCheck that the belt tensioner moves downward when
the drive belt is pressed down at the points indicated in
the illustration with approx. 98 N (10 kgf, 22.0 lbf) of
force.
w Check the ali gnment of the belt tensioner pulley to make
sure the drive belt will not slip off the pulley.
If necessary, replace the belt tensioner.
w Check that the arrow mark on the belt tensioner falls
within area A of the scale.
If it is outside area A, replace the drive belt.
HINT:
w When a new belt is installed, it should lie within area B.
If not, the drive belt is not correct.
w After installing a belt, check that it fits properly in the
ribbed grooves.
w Check by hand to confirm that the belt has not slipped
out of the groove on the bottom of the pulley.
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1UZ±FE ENGINE ENGINE MECHANICALEG±13
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(h) Disconnect the 2 engine wire connectors.
(i) Remove the 8 bolts, seal washers, cylinder head cover andgasket.
19. SET NO.1 CYLINDER TO TDC/COMPRESSION
(a) Turn the crankshaft pulley, and align its groove with timing mark ª0º of the No.1 timing belt cover.
(b) Check that the timing marks of the camshaft timing pulleys and timing belt rear plates aligned.
If not, turn the crankshaft 1 revolution (360 5) and align the
mark as above.
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1UZ±FE ENGINE ENGINE MECHANICALEG±19
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20. INSPECT VALVE CLEARANCE
(a) Check only the valves indicated.wUsing a feeler gauge, measure the clearance between
the valve lifter and camshaft
w Record the out±of±specification valve clearance
measurements. They will be used later to determine the
required replacement adjusting shim.
Valve clearance (Cold):
Intake0.15 ± 0.25 mm (0.006 ± 0.010 in.)
Exhaust 0.25 ± 0.35 mm (0.010 ± 0.014 in.)
(b) Turn the crankshaft 1 revolution (360
) and align the mark as
above. (See procedure in step 8)
(c) Check only the valves indicated as shown. Measure the valve
clearance. (See procedure in step (a))
21. REMOVE THEFT DETERRENT HORN
(a) Disconnect the connector.
(b) Remove the bolt and theft deterrent horn. HINT: Remove the deterrent horn when the valve clearance
is adjusted for the front portion of the exhaust camshaft on
the LH cylinder head.
EG±20
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(b) Determine the replacement adjusting shim size by followingthe Formula or Charts:
wUsing a micrometer, measure the thickness of the
removed shim.
w Calculate the thickness of a new shim so that the valve
clearance comes within specified value.
T 000 Thickness of removed shim
A 000 Measured valve clearance
N 000 Thickness of new shim
Intake:
N = T + (A ± 0.20 mm (0.008 in.))
Exhaust: N = T + (A ± 0.30 mm (0.012 in.))
w Select a new shim with a thickness as close as possible
to the calculated value.
HINT: Shims are available in 33 sized in increments of 0.025
mm (0.0010 in.) from 2.50 mm (0.0984 in.) to 3.30 mm
(0.1299 in.)
(c) Install a new adjusting shim. wPlace a new adjusting shim on the valve lifter.
w Using SST (A), press down the valve lifter and remove
SST (B).
SST 09248±05410, 09248±05021
(d) Recheck the valve clearance.
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1UZ±FE ENGINE ENGINE MECHANICALEG±23
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40. RECONNECT NEGATIVE TERMINAL CABLE TOBATTERY
41. REFILL WITH ENGINE COOLANT
42. START ENGINE AND CHECK FOR LEAKS
EG21T±02
IGNITION TIMING INSPECTION
1. REMOVE UPPER HIGH±TENSION CORD COVER
(a) Remove the 2 bolts.
(b) Disconnect the front side claw groove of the upper cord cover
from the claw of lower cord cover, and remove the upper cord
cover.
2. WARM UP ENGINE Allow the engine to warm up to normal operating tempera-
ture.
3. CONNECT TACHOMETER AND TIMING LIGHT TO ENGINE
Connect the tester probe of a tachometer to terminal IG
of
the DLC1.
HINT: Set the tachometer to the 4±cylinder range.
NOTICE:
w Never allow the tachometer terminal to touch ground as
it could result in damage to the igniter and/or ignition
coil.
w As some tachometers are not compatible with this
ignition system, we recommend that you confirm the
compatibility of your unit before use.
4. INSPECT IGNITION TIMING
(a) Using SST, connect terminals TE1 and E1 of the DLC 1.
SST 09843±18020
EG±32
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