engine LEXUS SC400 1991 Service Repair Manual

(b) Push the front side of the high±tension cord cover, andconnect the front side claw groove of the upper
high±tension cord cover to the claw of the lower
high±tension cord cover.
(c) Install the upper high±tension cord cover with the two bolts.
13. 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 con- nector
14. CONNECT CONTROL CABLES TO THROTTLE BODY Connect the following cables:(1) Accelerator cable
(2) A/T throttle control cable
(3) (w/ Cruise Control System) Cruise control actuator cable
15. INSTALL THROTTLE BODY COVER Install the throttle body cover and hose clamp with the two
bolts and cap nut.
16. C O N N E C T C A B L E TO N E G AT I V E T E R M I N A L O F BATTERY
17. FILL WITH ENGINE COOLANT (See page CO±7)
18. CHECK FOR FUEL LEAKS (See page FI±16) FI±41
EFI SYSTEM
± Fuel System (Cold Start Injector)
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Injectors
ON±VEHICLE INSPECTION
1. INSPECT INJECTOR OPERATIONCheck operation sound from each injector.
(a) With the engine running or cranking, use a stethescopeto check that there is normal operating noise in
proportion to engine rpm.
(b) If you have no stethescope, you can check the injector transmission operation with your finger.
If no sound or an unusual sound is heard, check the wiring
connector, injector or injection signal from the ECU.
2. INSPECT INJECTOR RESISTANCE (a) Disconnect the injector connector.
(b) Using an ohmmeter, measure the resistance betweenthe terminals.
Resistance: 13.4±14.2
at 20 5C (68 5F)
If the resistance is not as specified, replace the injector.
(c) Reconnect the injector connector.
FI±26
±
EFI SYSTEM Fuel System (Injectors)
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REMOVAL OF INJECTORS
(See Components on page FI±27 )
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OF
BATTERY
CAUTION: Turn the ignition switch to ºLOCKº.
Disconnect the cable from the negative (±) terminal of the
battery. Wait at least 20 seconds before proceeding with
work.
2. DRAIN ENGINE COOLANT
3. REMOVE THROTTLE BODY WITH INTAKE AIR CONNECTOR
(See steps 2 to 6 on pages EM±10 and 11)
4. DISCONNECT NO.1 FUEL PIPE FROM DELIVERY PIPE Remove the union bolt and two gaskets, and disconnect the
fuel pipe.
HINT:
wPut a suitable container or shop towel under the delivery
pipe.
w Slowly loosen the union bolt.
5. DISCONNECT NO. 2 FUEL PIPE FROM FUEL PRESSURE
REGULATOR
Remove the union bolt and two gaskets, and disconnect the
fuel pipe from the pressure regulator.
HINT:
w Put a suitable container or shop towel under the
pressure regulator.
w Slowly loosen the union bolt.
6. REMOVE AIR INTAKE CHAMBER STAYS Remove the bolt, nut and intake chamber stay.
Remove the No. 1 and No. 2 stays.
FI±28
±
EFI SYSTEM Fuel System (Injectors)
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(g) Install the grommet and a new O±ring to the injector.
(h) Connect SST (hose) to the injector with SST (union),and hold the injector and union with SST (clamp).
SST 09268±41045
(i) Put the injector into the graduated cylinder.
HINT: Install a suitable vinyl hose onto the injector to prevent
gasoline from splashing out.
(j) Using SST, connect terminals +B and FP of the check (ºDIAGNOSISº) connector.
SST 09843±18020
(k) Reconnect the cable to negative (±) terminal of battery.
(l) Turn the ignition switch ON.
NOTICE: Do not start the engine.
(m) Connect SST (wire) to the injector and battery for 15 seconds, and measure the injection volume with a
graduated cylinder. Test each injector two or three
times.
SST 09842±30070
Volume: 70±88 cm3 (4.3±5.4 cu in.) per 15 sec.
Difference between each injector:
9 cm
3 (0.5 cu in.) or less
If the injection volume is not as specified, replace the injector.
2. INSPECT LEAKAGE (a) In the condition above, disconnect the test probes ofSST (wire) from the battery and check the fuel leakage
from the injector.
SST 09842±30070
Fuel drop: One drop or less per minute
(b) Disconnect the battery negative (±) cable.
(c) Remove SST.
SST 09268±41045 and 09843±18020
(d) Reconnect the fuel inlet hose to the fuel tube.
SST 09631±22020
Torque: 30 N Vm (310 kgf Vcm, 22 ft Vlbf)
HINT: Use a torque wrench with a fulcrum length of 30 cm
(11.81 in.).
±
EFI SYSTEM Fuel System (Injectors)FI±31
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(b) Remove the bolt holding the intake air connector to thecylinder head cover.
(c) Loosen the two hose clamps.
(d) Disconnect the intake air connector from the throttle
body and air cleaner hose, and remove the intake air
connector.
3. REMOVE UPPER HIGH±TENSION CORD COVER (a) Remove the two mounting bolts.
(b) Disconnect the front side claw groove of the cord cover
from the claw of the lower cover, and remove the cord
cover.
4. REMOVE RH ENGINE WIRE COVER Remove the bolt and wire cover.
5. DISCONNECT VACUUM SENSING HOSE FROM FUEL PRESSURE REGULATOR
FI±44
EFI SYSTEM
± Fuel System (Fuel Pressure Regulator)
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(e) Connect the fuel return pipe to the pressure regulatorwith new two gaskets and the union bolt.
Torque: 35 N Vm (360 kgf Vcm, 26 ft Vlbf)
(f) Tighten the lock nut.
Torque: 29 N Vm (300 kgf Vcm, 22 ft Vlb)
2. CONNECT VACUUM SENSING HOSE TO FUEL
PRESSURE REGULATOR
3. INSTALL RH ENGINE WIRE COVER (a) Fit portions A and B of the engine wire cover, matchingthem with the lower high±tension cord cover and No.3
timing belt cover.
(d) Install the engine wire cover with the bolt.
FI±46
EFI SYSTEM
± Fuel System (Fuel Pressure Regulator)
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ENGINE SPEED SENSOR
COMPONENTS FOR REMOVAL AND
INSTALLATION
REMOVAL OF ENGINE SPEED SENSOR
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
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 the negative (±) termi-
nal cable is disconnected from the battery.
2. REMOVE ENGINE UNDER COVER
3. DISCONNECT ENGINE SPEED SENSOR CONNECTOR
4. REMOVE ENGINE SPEED SENSOR Remove the bolt and engine speed sensor.
INSTALLATION OF ENGINE SPEED
SENSOR
1. INSTALL ENGINE SPEED SENSOR
Torque: 6.4 N Vm (65 kgf Vcm, 56 in. Vlbf)
2. CONNECT ENGINE SPEED SENSOR CONNECTOR
3. INSTALL ENGINE UNDER COVER
4. CONNECT CABLE TO NEGATIVE TERMINAL OF
BATTERY
IG±30
±
IGNITION SYSTEM Engine Speed sensor
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IGNITION MAIN RELAY
INSPECTION OF IGNITION MAIN RELAY
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
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 the negative (±) termi-
nal cable is disconnected from the battery.
2. REMOVE IGNITION MAIN RELAY LOCATION: In the engine compartment relay box.
3. INSPECT IGNITION MAIN RELAY
A. Inspect relay continuity
(a) Using an ohmmeter, check that there is continuitybetween terminals 3 and 6.
(b) Check that there is continuity between terminals 4 and 5.
(c) Check that there is no continuity between terminals 1 and 2.
If continuity is not as specified, replace the relay.
B. Inspect relay operation (a) Apply battery voltage across terminals 3 and 6.
(b) Using an ohmmeter, check that there is continuitybetween terminals 1 and 2.
(c) Apply battery voltage across terminals 4 and 5.
(d) Using an ohmmeter, check that there is continuity between terminals 1 and 2.
If operation is not as specified, replace the relay.
4. REINSTALL IGNITION MAIN RELAY
5. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
±
IGNITION SYSTEM Ignition Main RelayIG±31
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SERVICE SPECIFICATIONS
SERVICE DATA
Ignition timing8±125 BTDC @ idlegg
(w/ Terminals TE1 and E1 connected)
Firing order1±8±4±3±6±5±7±2
Spark plugTypeNDPK20R11g
NGK BKR6EP11
Electrode gapNew plug STD 1.1 mm 0.043 in.
Used plug Limit 1.3 mm 0.051 in.
High±tensionResistance25 k
per cordg
cord
Ignition coilPrimary coil resistance0.40±0.50
gy
Secondary coil resistance10.0±14.0 k

Cam positionResistanceat ±10± +40 5C (14±104 5F)835±1,350

sensor
Engine speedResistanceat ±10± +40 5C (14±104 5F)835±1,350

sensor
TORQUE SPECIFICATIONS
Part tightenedNVmkgf Vcmft Vlbf
Spark plug X Cylinder head1818013
Cam position sensor X Distributor housing18185 13
Distributor cap X Distributor housing3.839 34 in. Vlbf
Distributor rotor X Camshaft timing pulley3.839 34 in. Vlbf
RH No.2 timing belt cover X Cylinder block (for 12 mm head)16160 12
Drive belt idler pulley X Hydraulic pump37380 27
Engine speed sensor X Oil pump6.46556 in. Vlbf
IG±32±
IGNITION SYSTEM Service Specifications
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DESCRIPTION
The ECU is programmed with data for optimum ignition timing under any and a\
ll operating conditions. Using
data provided by sensors which monitor various engine functions (rpm, i\
ntake air volume, engine temperature,
etc.) the microcomputer (ECU) triggers the spark at precisely the right ins\
tant.
The ECU monitors the engine condition by signals from each sensor, calculates the ignition timing and sends
an ignition signal to the igniter. High voltage from the ignition is distributed to each spark plug in th\
e appropriate
order to generate a spark between the electrodes, which ignites the air±fu\
el mixture.
IGNITERS The igniter temporarily interrupts the primary current with the ignition si\
gnal (IGT signal) from the ECU and
generates sparks at the spark plug. Also, as a fail±safe measure, when ignitio\
n occurs, an ignition confirmation
signal (IGF signal) is sent to the ECU.
IGNITION COIL
The ignition coil uses a closed core coil with the primary coil wrapped \
around the core and the secondary
coil wrapped around the primary coil. This allows the generation of a hi\
gh voltage sufficient to cause a spark
to jump across the spark plug gap.
DISTRIBUTORS
This correctly distributes high voltage to the spark plug of each cylind\
er in the specified ignition order.
ENGINE SPEED SENSOR The engine speed sensor detects the crank angle.
CAM POSITION SENSORS The RH and LH cam position sensors detect the cam angle.
IG±2
±
IGNITION SYSTEM Description
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