vacuum LEXUS SC400 1991 Service Owner's Guide

(b) Install the EGR valve with the two nuts.
Torque: 18 NVm (185 kgf Vcm, 13 ft Vlbf)
(c) Connect the following hoses:
(1) Water by±pass hose (from ISC valve) to the EGR valve
(2) Water by±pass hose (from rear water by±pass joint) to the EGR valve
8. RECONNECT EGR VALVE CONNECTOR
9. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
10. REFILL WITH ENGINE COOLANT (See page CO±7)
INSPECTION OF EGR VALVE
(Exc. USA Spec.)
1. DRAIN ENGINE COOLANT (See page CO±6)
2. REMOVE EGR VALVE (a) Disconnect the following hoses:(1) Vacuum hose (from VSV) from EGR valve
(2) Vacuum hose (from VSV) from EGR vacuum
modulator
(3) Vacuum hose (from EGR vacuum modulator) f rom EGR valve
(4) Water by±pass hose (from ISC valve) from the
EGR valve
(5) Water by±pass hose (from rear water by±pass joint) from the EGR valve
(b) Disconnect the vacuum modulator bracket from the
EGR valve.
(c) Remove the two nuts, EGR valve and gasket.
EC±24
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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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)
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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SERVICE SPECIFICATIONS
SERVICE DATA
EG065±0A Tune±up Battery specific gravity  1.27±1.29
    (when fully charged at 205C (68 5F))
  High±tension cord resistance Limit 25 k
per cord
  Valve clearance (Cold) Intake 0.15±0.25 mm (0.006±0.010 in.)
   Exhaust 0.25±0.35 mm (0.010±0.014 in.)
Valve clearance adjusting shimNo.012.500 mm (0.0984 in.)   No.62 2.525 mm (0.0994 in.)   No.63 2.550 mm (0.1004 in.)   No.64 2.575 mm (0.1014 in.)   No.06 2.600 mm (0.1024 in.)
   No.65 2.625 mm (0.1033 in.)
   No.66 2.650 mm (0.1043 in.)
   No.67 2.675 mm (0.1053 in.)
   No.13 2.700 mm (0.1063 in.)
   No.68 2.725 mm (0.1073 in.)
   No.18 2.750 mm (0.1083 in.)
No.192.775 mm (0.1093 in.)   No.23 2.800 mm (0.1102 in.)   No.70 2.825 mm (0.1112 in.)   No.28 2.850 mm (0.1122 in.)   No.71 2.875 mm (0.1132 in.)
   No.33 2.900 mm (0.1142 in.)
   No.72 2.925 mm (0.1152 in.)
   No.38 2.950 mm (0.1161 in.)
   No.73 2.975 mm (0.1171 in.)
   No.43 3.000 mm (0.1181 in.)
No.743.025 mm (0.1191 in.)   No.48 3.050 mm (0.1201 in.)   No.75 3.075 mm (0.1211 in.)   No.51 3.100 mm (0.1220 in.)   No.76 3.125 mm (0.1230 in.)   No.77 3.150 mm (0.1240 in.)
   No.78 3.175 mm (0.1250 in.)
   No.56 3.200 mm (0.1260 in.)
   No.79 3.225 mm (0.1270 in.)
   No.80 3.250 mm (0.1280 in.)
   No.81 3.275 mm (0.1289 in.)
No.613.300 mm (0.1299 in.)  Ignition timing  8 ± 12 5 BTDC @ idle 


 


 


 

(w/ Terminals TE1 and E1 connected
of DLC1)
  Idle speed  700
+ 50 rpm
 Intake at idle speed  60 kPa (450 mmHg. 17.7 in.Hg)
 manifold
 vacuum   
±
1UZ ± FE ENGINE ENGINE MECHANICALEG±205
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(b) Disconnect the following hoses:(1) Water bypass hose from IAC valve
(2) California: Vacuum hose from throttle body
(3) Except California: 3 vacuum hoses from throttle body
(c) Remove the 2 bolts and 2 nuts, and disconnect the throttle body from the air intake chamber.
(d) Disconnect the following hoses, and remove the throttle body.
(1) PCV hose from throttle body
(2) Water bypass hose from throttle body
(e) Remove the throttle body gasket.
17. REMOVE RH CYLINDER HEAD COVER
(a) Disconnect the No.2 high±tension cord from the cord clamp on the front high±tension cord clamp.
(b) Remove the 2 bolts holding the high±tension cord clamps to the cylinder head cover.
(c) Disconnect the 5 high±tension cords from the front side of the
front high±tension cord clamp.
(d) Disconnect the front high±tension cord clamp from the lower high±tension cord cover.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±17
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(n) Connect the No. 1 high±tension cord to the cord clamp on the
front high±tension cord clamp.
26. REINSTALL THROTTLE BODY
(a) Disconnect the following hoses: (1) PCV hose to throttle body
(2) Water bypass hose to throttle body
(b) Install a new gasket and throttle body with the 2 bolts and 2 nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the water bypass pipe (from the rear bypass joint) to
the clamp on the engine wire cover.
(d) Connect the following hoses: (1) Water bypass hose to IAC valve
(2) California:Vacuum hose from throttle body
(3) Except California: 3 vacuum hoses from throttle body
EG±28
±
1UZ±FE ENGINE ENGINE MECHANICAL
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EG115±06
IDLE SPEED INSPECTION
1. INITIAL 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 connectedHINT: All vacuum hoses for EGR system, etc. should be prop-
erly connected.
(f) MFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
2. CONNECT TACHOMETER 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.
3. INSPECT IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
700 + 50 rpm
If the idle speed is not as specified, check the IAC valve.
4. DISCONNECT TACHOMETER
EG±34
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1UZ±FE ENGINE ENGINE MECHANICAL
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IDLE AND/OR 2,500 RPM CO/HC
CHECK
EG116±05
HINT: This check is used only to determine whether or not the
idle CO/HC complies with regulations.
1. INITIAL 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 system, etc. should be prop-
erly connected.
(f) MFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
(i) Tachometer and CO/HC meter calibrated by hand
2. START ENGINE
3. RACE ENGINE AT 2,500 RPM FOR APPROX. 180 SECONDS
4. INSERT CO/HC METER TESTING PROBE INTO TAILPIPE AT LEAST 40 cm (1.3 ft) DURING IDLING
5. IMMEDIATTELY CHECK CO/HC CONCENTRATION AT
IDLE AND/OR 2,500 RPM
HINT: When performing the 2 mode (2,500 rpm and idle) test,
follow the measurement order prescribed by the applicable
local regulations.
±
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Troubleshooting
If the CO/HC concentration does not comply with regulations,
perform troubleshooting in the order given below.
(a) Check main heated oxygen sensor operation.
(See MFI System on page EG±400)
(b) See the table below for possible causes, and then inspect and correct the applicable causes if necessary.
 CO HC Problems\
 \
Causes
 Normal High Rough idle\
 \
1. Faulty ignitions: 


 


 


\
 

\

Incorrect timing
   \
 \
Fouled, shorted or improperly gapped plugs
   \
 \
Open or crossed high±tension cords
   \
 \
Cracked distributor cap
   \
 \
2. Incorrect valve clearance   \
 \
3. Leaky EGR valve 


 


 


\
 

\
4. Leaky intake and exhaust valves
   \
 \
5. Leaky cylinder
 Low High Rough idle\
 \
1. Vacuum leaks:
   (Fluctuating HC reading)\
 \

PCV hose
   \
 \
EGR valve 


 


 


\
 

\

Intake manifold
   \
 \
Throttle body
   \
 \
IAC valve
   \
 \
Brake booster line
   \
 \
2. Lean mixture causing misfire 

High 

High 

Rough idle\
 

\
1. Restricted air filter
   (Black smoke from exhaust)\
 \
2. Faulty MFI systems:
   \
 \

Faulty pressure regulator
   \
 \
Clogged fuel return line
   \
 \
Defective ECT switch   \
 \
Faulty ECM 


 


 


\
 

\

Faulty injector
   \
 \
Faulty throttle position sensor
   \
 \
Faulty volume air flow meter
V02130
EG±36±
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EG24R±02
CYLINDER HEADS REMOVAL
(See Components for Removal and Installation)
1. DISCONNECT TIMING BELT FROM CAMSHAFT TIMING PULLEYS
(See steps 1 to 29 on pages EG±46 to 54)
2. REMOVE CAMSHAFT TIMING PULLEYS Using SST, remove the bolt and timing pulley. Remove the 2
timing pulleys.
SST 09278±54012
3. REMOVE FAN BRACKET Remove the 2 bolts, 2 nuts and fan bracket.
NOTICE:
w Be careful not to drop anything inside the timing belt
cover.
w Do not allow the belt to come into correct with oil, water
or dust.
4. DISCONNECT POWER STEERING (PS) PUMP FROM
ENGINE
(a) Disconnect the vacuum hose from the air intake chamber.
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1UZ±FE ENGINE ENGINE MECHANICALEG±75
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9. REMOVE WATER INLET AND INLET HOUSING
(a) Disconnect the water bypass hose from the IAC valve.
(b) Remove the 2 bolts holding the water inlet housing to waterpump.
(c) Pull out the water inlet and inlet housing assembly.
(d) Remove the O±ring from the water inlet housing.
10. REMOVE TIMING BELT REAR PLATES
Remove the 2 bolts and rear plate. Remove the 2 rear plates.
11. REMOVE VACUUM PIPE
(a) Disconnect the following hoses: (1) California:
Vacuum hose from throttle body
(2) Except California: 3 vacuum hoses from throttle body
(3) Vacuum hose from fuel pressure regulator
(4) 2 vacuum hoses from VSV for fuel pressure control
(5) Except California:
2 vacuum hoses from EGR vacuum modulator
(6) 2 vacuum hoses (from VSV for EVAP) from vacuum pipe
(7) Vacuum hose (from VSV for fuel pressure) from air in-
take chamber
(8) Vacuum hose (from charcoal canister) from vacuum pipe
±
1UZ±FE ENGINE ENGINE MECHANICALEG±77
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