ignition LEXUS SC300 1991 Service Repair Manual

28. INSTALL HIGH±TENSION CORDS, HIGH±TENSIONCORD CLAMP AND LOWER HIGH±TENSION CORD
COVER ASSEMBLY
(a) Install the lower high±tension cord cover with the bolt.
(b) Connect the high±tension cord to RH ignition coil.
(c) Connect the four high±tension cord to the RH sparkplugs.
(d) Install the RH rear and front high±tension cord clamps
with the two bolts.
HINT: Place the front and rear ends of the front hightension
cord clamp on the rear high±tension cord clamp and lower
high±tension cord cover.
(e) Connect the four high±tension cord to the LH spark plugs.
(f) Install the LH rear and front high±tension cord clamps
with the two bolts.
HINT: Place the front and rear ends of the front hightension
cord clamp on the rear high±tension cord clamp and lower
high±tension cord cover.
(g) Fit the high±tension cords to the high±tension cord clamp. (See page IG±16)
29. INSTALL RH NO.3 TIMING BELT COVER (a) Install the three gaskets to the timing belt cover.
(b) Fit portion A of the timing belt cover, matching it with the
lower high±tension cord cover.
(c) Install the timing belt cover with the three bolts.
30. INSTALL VSV FOR EVAP SYSTEM Install the VSV with the two bolts.
EM±54
±
ENGINE MECHANICAL Timing Belt
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35. INSTALL LH IGNITION COIL(a) Install the ignition coil with the two bolts.
(b) Connect the following connectors and cord:(1) Ignition coil connector
(2) Noise filter connector
(3) High±tension cord
36. INSTALL INTAKE AIR CONNECTOR (a) Connect the end portions of the intake air connector tothe throttle body and air cleaner hose.
(b) Tighten the two hose clamps.
(c) Install the bolt holding the intake air connector to the cylinder head cover.
(d) Connect the following hoses: (1) Air hose to ISC valve
(2) Air hose (from PS air control valve) to intake air connector
EM±56
±
ENGINE MECHANICAL Timing Belt
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37. INSTALL A/C COMPRESSOR(a) In sta ll th e A/C co mp re sso r, co mp re sso r sta y an dground cable with the three bolts and nut.
Torque: Bolt 49 N Vm (500 kgf Vcm, 36 ft Vlbf)
Nut 29 N Vm (300 kgf Vcm, 22 ft Vlbf)
(b) Connect the A/C compressor connector.
38. INSTALL RADIATOR AND RESERVOIR TANK (See steps 25 and 26 on pages EM±174 to 175)
39. INSTALL DRIVE BELT Install the drive belt by turning the drive belt tensioner coun-
terclockwise.
HINT: The pully bolt for the belt tensioner has a lefthand
thread.
40. INSTALL BATTERY
41. FILL WITH ENGINE COOLANT (See page CO±7)
42. CHECK IGNITION TIMING (See page IG±28)
Ignition timing:
8±125 BTDC @ idle
(w/ Terminals TE1 and E1 connected)
43. INSTALL ENGINE UNDER COVER
±
ENGINE MECHANICAL Timing BeltEM±57
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5. REMOVE THROTTLE BODY COVER(a) Remove the mounting cap nut.
(b) Loosen the two bolts, and remove the throttle bodycover.
6. DISCONNECT CONTROL CABLES FROM THROTTLE BODY
Disconnect the following cables:(1) Accelerator cable
(2) A/T throttle control cable
(3) (w/ Cruise Control System) Cruise control actuator cable
7. REMOVE RH IGNITION COIL Remove the two bolts and ignition coil.
8. REMOVE WATER INLET AND INLET HOUSING (a) Disconnect the water by±pass hose from the ISC valve.
(b) Remove the two bolts holding the water inlet housing to the water pump.
(c) Pull out the water inlet and inlet housing assembly.
(d) Remove the O±ring from the water inlet housing.
±
ENGINE MECHANICAL Cylinder HeadsEM±61
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43. INSTALL RH IGNITION COILInstall the ignition coil with the two bolts.
44. CONNECT CONTROL CABLES TO THROTTLE BODY Connect the following cables:(1) Accelerator cable
(2) A/T throttle cable
(3) (w/ Cruise Control System)
Cruise control actuator cable
45. INSTALL THROTTLE BODY COVER Install the throttle body cover and hose clamp with the two
bolts and cap nut.
46. INSTALL CATALYTIC CONVERTERS (MAIN) (a) Install a new gasket and the catalytic converter to theexhaust manifold with the three new bolts. Install the two
catalytic converters.
Torque: 62 N Vm (630 kgf Vcm, 46 ft Vlbf)
(b) Install a new gasket to each front end of the front
exhaust pipe.
(c) C onnect the front exhaust pipe to the catalytic
converters.
(d) Te mp o ra rily in sta ll th e fo u r bo lts ho ld in g th e pip e support bracket to the transmission.
(e) Install the four bolts and nuts holding the catalytic
converters to the front exhaust pipe.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
(f) Tighten the four bolts holding the pipe support bracket
to the transmission.
Torque: 43 N Vm (440 kgf Vcm, 32 ft Vlbf)
EM±114±
ENGINE MECHANICAL Cylinder Heads
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COMPONENTS FOR REMOVAL AND
INSTALLATION OF ENGINE WITH
TRANSMISSION (Cont'd)
REMOVAL OF ENGINE WITH
TRANSMISSION
1. REMOVE BATTERYCAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and the negative (±) termi-
nal cable is disconnected from the battery.
2. REMOVE ENGINE UNDER COVER
3. DRAIN ENGINE COOLANT (See page CO±6)
4. DRAIN ENGINE OIL
5. REMOVE HOOD
6. REMOVE DRIVE BELT Loosen the drive belt tension by turning the drive belt tension-
er counterclockwise, and remove the drive belt.
HINT: The pulley bolt for the belt tensioner has a left±hand
thread.
EM±118
±
ENGINE MECHANICAL Cylinder Block
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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
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SERVICE SPECIFICATIONS
SERVICE DATA
 Engine tune±up Battery specific gravity  1.27±1.29 g  (when fully charged at 205C (68 5F))  High±tension cord resistance Limit 25 k
per cord  Valve clearance Intake 0.15 ± 0.25 mm 0.006 ± 0.010 in.   Exhaust 0.25 ± 0.35 mm 0.010 ± 0.014 in.
  Ignition timing 8±12 5 BTDC @ idle
   (w/ Terminals TE1 and E1 connected)
  Idle speed 700 + 50 rpm
 


Intake
manifold 


at Idle speed 


 


60 kPa 450 mmHg 17.7 in.Hg
vacuum vacuum  
Compressionat 250 rpmSTD1,226 kPa (12.5 kgf/cm, 178 psi) or more pressure  Limit 981 kPa 10.0 kgf/cm 142 psi  Difference of pressure between each cylinder 98 kPa (1.0 kgf/cm, 14 psi) or less Timing belt ten- Protrusion from housing end 10.5 ± 11.5 mm 0.413 ± 0.453 in. g
sioner g  
 Cylinder head Warpage Cylinder block side Limit 0.10 mm 0.0039 in.
 
y
 Manifold side Limit 0.10 mm 0.0039 in.
  Valve seat Refacing angle 30
5, 45 5, 75 5
  Contacting angle 455
Contacting width1.0 ± 1.4 mm0.039 ± 0.055 in.  Cylinder head bolt thread outside diam4eter 
   STD 9.770 ± 9.960 mm 0.3846 ± 0.3921 in.   Limit 9.60 mm 0.3780 in. Valve guide Inside diameter 6.010 ± 6.030 mm 0.2366 ± 0.2374 in.
 
g
bushing Outside diameter (for repair part) STD 11.048 ± 11.059 mm 0.4350 ± 0.4354 in.
 
g
  O/S 0.05 11.098 ± 11.109 mm 0.4369 ± 0.4374 in.
 Valve Valve overall length STD Intake 94.95 mm 3.7382 in.
    Exhaust 96.90 mm 3.8150 in.
LimitIntake94.45 mm3.7185 in.    Exhaust 96.40 mm 3.7953 in.  Valve face angle   44.5 5  Stem diameter  Intake 5.970 ± 5.985 mm 0.2350 ± 0.2356 in.    Exhaust 5.965 ± 5.980 mm 0.2356 ± 0.2354 in.
  Stem oil clearance STD Intake 0.025 ± 0.060 mm 0.0010 ± 0.0024 in.
    Exhaust 0.030 ± 0.065 mm 0.0012 ± 0.0026 in.
   Limit Intake 0.08 mm 0.0031 in.
Exhaust0.10 mm0.0039 in.  Margin thickness  STD 1.0 mm 0.039 in.    Limit 0.5 mm 0.020 in. Valve spring Squareness Limit 2.0 mm 0.079 in. g Free length  43.6 mm 1.717 in.
  Installed tension at 32.9 mm (1.295 in.) 186±206 N 
    (19.0 ± 21.0 kgf, 41.9 ± 46.3 lbf)
 Valve lifter Lifter diameter 30.966±30.976 mm 1.2191±1.2195 in.
  Lifter bore diameter  31.000±31.016 mm 1.2205±1.2211 in.
Oil clearanceSTD0.024±0.050 mm0.0009±0.0020 in.   Limit 0.07 mm 0.0028 in.
EM±178±
ENGINE MECHANICAL Service Specifications
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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
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ELECTRONIC CONTROL SYSTEM
The control system consists of sensors which detect various engine conditions, and a ECU which deter\
-
mines the injection volume (timing) based on the signals from the sens\
ors.
The various sensors detect the air intake volume, engine rpm, oxygen densit\
y in the exhaust gas, coolant
temperature, air intake temperature and atmospheric pressure etc. and convert the in\
formation into an electrical
signal which is sent to the ECU. Based on these signals, the ECU calculates th\
e optimum ignition timing for the
current conditions and operates the injectors.
The ECU not only controls the fuel injection timing, but also the self diag\
nostic function which records the
occurrence of a malfunction, ignition timing control, idle rpm control, \
EGR control, EVAP control, fuel pressure
control and fuel pump control. FI±9
EFI SYSTEM
± Operation
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