check engine LEXUS SC400 1991 Service Repair Manual

INSPECTION OF CRANKSHAFT
1. INSPECT CRANKSHAFT FOR RUNOUT(a) Place the crankshaft on V±blocks.
(b) Using a dial indicator, measure the circle runout at thecenter journal.
Maximum circle runout: 0.08 mm (0.0031 in.)
If the circle runout is greater than maximum, replace the
crankshaft.
2. INSPECT MAIN JOURNALS AND CRANK PINS (a) Using a micr ometer, measure the diameter of each main
journal and crank pin.
Main journal diameter: 66.988±67.000 mm
(2.6373±2.6378 in.)
Crank pin diameter: 51.982±52.000 mm (2.0465±2.0472 in.)
If the diameter is not as specified, check the oil clearance
(See page EM±136 or 139).
(b) Check each main journal and crank pin for taper and out±of±round as shown.
Maximum taper and out±of±round: 0.02 mm
(0.0008 in.)
If the taper or out±of±round is greater than maximum, re-
place the crankshaft.
±
ENGINE MECHANICAL Cylinder BlockEM±151
WhereEverybodyKnowsYourName

(c) Mark the front of the main bearing cap nut with paint.
(d) R e t i g h t e n t h e m a i n b e a r i n g c a p n u t s 9 0 5 i n t h enumerical order shown.
(e) Check that the painted mark is now at a 905 angle to the
front.
(f) Check that the crankshaft turns smoothly.
(g) Check the crankshaft thrust clearance. (See step 5 on page EM±138)
C. Install main bearing cap bolts (a) Install a new seal washer to the main bearing cap bolt.
(b) Install the ten main bearing cap bolts.
Torque: 49 N Vm (500 kgf Vcm, 36 ft Vlbf)
5. INSTALL PISTON AND CONNECTING ROD ASSEMBLIES
Using a piston ring compressor, push the correctly numbered
piston and connecting rod assemblies into each cylinder with
the front mark of the piston facing forward.
NOTICE: The shape of the piston varies for the RH and LH
banks. The RH piston is marked with ºRº, the LH piston
with ºLº.
EM±158
±
ENGINE MECHANICAL Cylinder Block
WhereEverybodyKnowsYourName

6. INSTALL CONNECTING ROD CAPS
A. Place connecting rod cap on connecting rod(a) Match the numbered c onnecting rod cap with the
connecting rod.
(b) Align the pin groove of the connecting rod cap with the pins of the connecting rod, and install the connecting rod
cap.
(c) Check that the outside mark on the connecting rod cap is facing in correct direction.
B. Install connecting rod cap bolts HINT:
wThe connecting rod cap bolts are tightened in two
progressive steps (steps (b) and (d)).
w If any one of the connecting rod bolts is broken or
deformed, replace it.
(a) Apply a light of engine oil on the threads and under the
heads of the connecting rod cap bolts.
(b) Usin g SS T, in sta ll an d alte rn a te ly tig h te n th e two connecting rod cap bolts in several passes.
SST 09011±38121
Torque: 25 N Vm (250 kgf Vcm, 18 ft Vlbf)
If any one of the connecting rod cap bolts does not meet the
torque specification, replace the connecting rod cap bolt.
(c) Mark the front of the connecting rod cap bolt with paint.
±
ENGINE MECHANICAL Cylinder BlockEM±159
WhereEverybodyKnowsYourName

(d) Retighten the connecting rod cap bolts 905 in thenumerical order shown.
(e) Check that the painted mark is now at a 905 angle to the
front.
(f) Check that the crankshaft turns smoothly.
(g) Check the connecting rod thrust clearance. (See step 2 on page EM±135)
7. INSTALL REAR OIL SEAL RETAINER (a) Remove any old packing (FIPG) material and be carefulnot to drop any oil on the contact surfaces of the retainer
and cylinder block.
w Using a razor blade and gasket scraper, remove all the
old packing (FIPG) material from the gasket surfaces
and sealing groove.
w Thoroughly clean all components to remove all the
loose material.
w Using a non±residue solvent, clean both sealing
surfaces.
(b) Apply seal packing to the retainer as shown in the illustration.
Seal packing: Part No.08826±00080 or equivalent
wInstall a nozzle that has been cut to a 2±3 mm
(0.08±0.12 in.) opening.
w Parts must be assembled within 3 minutes of
application. Otherwise the material must be removed
and reapplied.
w Immediately remove nozzle from the tube and reinstall
cap.
(c) Place a new O±ring in position on the cylinder block.
(d) Install the retainer with the seven bolts.
Torque: 7.8 N Vm (80 kgf Vcm, 69 in. Vlbf)
EM±160±
ENGINE MECHANICAL Cylinder Block
WhereEverybodyKnowsYourName

9. INSTALL CATALYTIC CONVERTERS (MAIN)Install a new gasket and the catalytic converter with three
new nuts. Install the two catalytic converters.
Torque: 62 N Vm (630 kgf Vcm, 46 ft Vlbf)
10. INSTALL FRONT EXHAUST PIPE
(a) Temporarily install the pipe support stay with the fourbolts.
(b) Install three new gaskets, the exhaust pipe and pipe support stay with the six bolts and nuts.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
(c) Tighten the four bolts holding the pipe support bracket
to the transmission.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
(d) Install the two sub±oxygen sensors to the exhaust pipe.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
HINT:
w Before installing the s ub±oxygen sensor, twist the
sensor wire counterclockwise 3 1/2 turns.
w After installing the sub±oxygen sensor, check that the
sensor wire is not twisted. If it is twisted, remove the
sub±oxygen sensor and reinstall it.
(e) Install the wire grommets to the floor.
11. CONNECT ENGINE WIRE TO CABIN (a) Push in the engine wire through the cowl panel.
(b) Install the engine wire clamp with the three bolts.
±
ENGINE MECHANICAL Cylinder BlockEM±169
WhereEverybodyKnowsYourName

31. INSTALL THROTTLE BODY COVERInstall the throttle body cover and hose clamp with the two
bolts and cap nut.
32. INSTALL DRIVE BELT Install the drive belt by turning the drive belt tensioner coun-
terclockwise.
HINT: The pulley bolt for the belt tensioner has a left±hand
thread.
33. INSTALL BATTERY
34. FILL WITH ENGINE COOLANT (See page CO±7)
35. FILL COOLING FAN RESERVOIR TANK WITH FLUID (See page CO±23)
36. FILL WITH ENGINE OIL (See page LU±7)
Capacity:
Drain and refill
w/Oil filter change4.8 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)
Dry fill 6.0 liters (6.3 US qts, 5.3 lmp. qts)
37. START ENGINE AND CHECK FOR LEAKS
38. CHECK AUTOMATIC TRANSMISSION FLUID LEVEL
39. CHECK IGNITION TIMING (See page IG±28)
Ignition timing:
8±125 BTDC @ idle
(w/ Terminals TE1 and E1 connected)
40. INSTALL ENGINE UNDER COVER
41. INSTALL HOOD
42. PERFORM ROAD TEST Check for abnormal noise, shock, slippage, correct shift
points and smooth operation.
32. RECHECK ENGINE COOLANT AND ENGINE OIL LEVELS
±
ENGINE MECHANICAL Cylinder BlockEM±177
WhereEverybodyKnowsYourName

The EFI system is composed of three basic sub±systems: Fuel, Air Induction and Elect\
ronic Control
Systems.
FUEL SYSTEM
An electric pump fuel pressure supplies sufficient fuel, under a constant pressure, to the EFI injectors. In
accordance with signals from the ECU (Electronic Control Unit), these \
injectors inject the quantity of fuel most
appropriate for the engine condition into the intake manifold.
AIR INDUCTION SYSTEM
The air induction system provides sufficient air for engine operation.
ELECTRONIC CONTROL SYSTEM
The 1UZ±FE engine (ECU±formerly EFI computer) with a microcomputer \
centrally controls the EFI, ESA,
ISC and Diagnosis system, etc. The ECU controls the following functions:
1. Electronic Fuel Injection (EFI)
The ECU receives signals from various sensors indicating changing engine op\
eration conditions such as:Intake air volume
Intake air temperature
Coolant temperature
Engine rpm
Acceleration/deceleration
Exhaust oxygen content etc.
The signals are utilized by the ECU to determine the injection duration nec\
essary for an optimum air±fuel
ratio.
2. Electronic Spark Advance (ESA) The ECU is programmed with data for optimum ignition timing under any and all opera\
ting conditions. Using
data provided by sensors which monitor various engine functions (rpm, coola\
nt temperature, etc.), the
Electronic Control Unit (ECU) triggers the spark at precisely right instant. (S\
ee IG section)
3. Idle Speed Control (ISC) The ECU is programmed with idle speed data for various engine conditions (\
coolant temperature, air condi-
tioner ON/OFF, etc.).
The air volume flowing through the throttle valve by±pass passage is adj\
usted according to the signal from
each sensor and the idle speed is kept at the set value.
4. Diagnosis Function When the ECU detects any malfunctions or abnormalities in the sensor network\
, it lights the ºCHECKº en-
gine warning light in the combination meter. At the same time, the trouble is identified and a diagnostic code
is recorded by the ECU. The diagnostic code can be read by the number of\
blinks of the ºCHECKº engine
warning light when terminals TE1 and E1 are connected. The diagnostic co\
des are refer to the later page.
(See TR section)
5. Self±Correction Function If any sensor malfunctions, an average value recorded in the back±up ci\
rcuit is substituted to make driving
possible.
If danger is predicted, the engine is stopped and the ºCHECKº engine\
warning light will light up.
6. Fail±Safe Function Even if an abnormality occurs in the ECU, the back±up circuit uses a specifie\
d fuel injection and ignition
timing to provide vehicle driveability, and also lightsup the ºCHECKº engine warning light.
FI±4
EFI SYSTEM
± Description
WhereEverybodyKnowsYourName

Preparation
SST (SPECIAL SERVICE TOOLS)
IllustrationPart No.Part NameNote
09268±41045Injection Measuring
Tool Set
(90268±41070)No. 4 Union
Injector
(09268±41080)No. 6 Union
Cold start Injector
(09268±52010)Injection Measuring
Attachment
Injector
09268±45012EFI Fuel Pressure
Gauge
09612±24014
Steering Gear
Housing Overhaul
Tool Set
(09617±24011)Steering Rack Wrench
Fuel pressure pulsation damper
09631±22020
Power Steering
Hose Nut 14 X 17 mm
Wrench SetFuel line flare nut
09816±30010Oil Pressure
Switch SocketKnock sensor
09842±30055Wire ªGº
EFI Inspection
Cold start Injector
09842±30070Wire ªFº
EFI Inspection
Injector
09843±18020Diagnosis Check
Wire
0990±01000
Engine Control
Computer
Check Harness ªAº
FI±10 ± PreparationEFI SYSTEM
WhereEverybodyKnowsYourName

PRECAUTIONS
1. Before working on the fuel system, disconnect the cablefrom negative (±) terminal of the battery.
HINT: Any diagnostic code retained by the computer will be
erased when the battery terminal is removed. Therefore, if
necessary, read the diagnosis before removing the battery
terminal.
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 negative (±) terminal
cable is disconnected from the battery.
2. Do not smoke or work on open flame when working on the fuel system.
3. Keep gasoline away from rubber or leather parts.
INSPECTION PRECAUTIONS
MAINTENANCE PRECAUTIONS
1. CHECK CORRECT ENGINE TUNE±UP (See page EM±8)
2. PRECAUTIONS WHEN CONNECTING GAUGE (a) Use the battery as the power source for the timing light,tachometer, etc.
(b) Connect the test probe of a tachometer to the terminal IG of the check connector.
3. IN EVENT OF ENGINE MISFIRE, FOLLOWING PRECAUTIONS SHOULD BE TAKEN
(a) Check proper connection of battery terminals, etc.
(b) Handle high±tension cords carefully.
(c) After repair work, check that the ignition coil terminalsand all other ignition system lines are reconnected
securely.
(d) When cleaning the engine compartment, be especially careful to protect the electrical system from water.
4. PRECAUTIONS WHEN HANDLING OXYGEN SENSOR (a) Do not allow oxygen sensor to drop or hit against anobject.
(b) Do not allow the sensor to come into contact with water.
FI±12
± Precautions, Inspection PrecautionsEFI SYSTEM
WhereEverybodyKnowsYourName

FUEL SYSTEM
Fuel Pump
ON±VEHICLE INSPECTION
1. CHECK FUEL PUMP OPERATION(a) Using SST, connect terminals +B and FP of the check
(ºDIAGNOSISº) connector.
SST 09843±18020
(b) Turn the ignition switch ON.
NOTICE: Do not start the engine.
(c) Check that there is pressure in the fuel inlet hose from the fuel filter.
HINT: At this time, you will hear fuel return noise.
(d) Turn the ignition switch OFF.
(e) Remove SST from the check connector.
SST 09843±18020 FI±17
± Fuel System (Fuel Pump)EFI SYSTEM
WhereEverybodyKnowsYourName