1991 LEXUS SC400 fuel pressure

ABBREVIATIONS USED IN THIS
MANUAL
ABS Anti±Lock Brake System J/B Junction Block
A/C Air Conditioner LED Light Emitting Diode
ALR Automatic Locking Retractor LH Left±Hand
APPROX. Approximation LHD Left±Hand Drive
A/T, ATM Automatic Transmission LLC Long Life Coolant (Year Around Coolant)
ATF Automatic Transmission Fluid Max. Maximum
BTDC Before Top Dead Center Min. Minimum
BVSV Bimetal Vacuum Switching Valve MP Multipurpose
CALIF. Vehicles Sold in California N Neutral
CB Circuit Breaker OD, O/D Overdrive
DOHC Double Over Head Cam O/S Oversize
DP Dash Pot P & BV Proportioning and Bypass Valve
ECT Electronic Controlled Transmission PCV Positive Crankcase Ventilation
ECU Electronic Controlled Unit PS Power Steering
EFI Electronic Fuel Injection RH Right±Hand
EGR Exhaust Gas Recirculation RL Rear Left
ELR Emergency Locking Retractor RR Rear Right
EPR Evaporator Pressure Regulator RR, Rr Rear
ESA Electronic Spark Advance SRS Supplemental Restraint System
EVAP Evaporative (Emission Control) SSM Special Service Materials
EX Exhaust (manifold, valve) SST Special Service Tools
Ex. Except STD Standard
FIPG Formed in Place Gasket SW Switch
FL Front Left TDC Top Dead Center
FL Fusible Link TDCL Total Diagnostic Communication Link
FPU Fuel Pressure Up Temp. Temperature
FR Front Right TRAC Traction Control System
FR, Fr Front TWC Three±Way Catalyst
HAC High Altitude Compensation VSV Vacuum Switching Valve
IG Ignition VTV Vacuum Transmitting Valve
IN Intake (manifold, valve) w/ With
INT Intermittent w/o Without
ISC Idle Speed Control
IN±34±
INTRODUCTION Abbreviations Used in This Manual
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wTighten the O±ring fittings or the bolted type fittings to
the specified torque.
Precautions When Charging Refrigerant
1. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH
REFRIGERANT IN REFRIGERANT CYCLE
If there is not enough refrigerant in the refrigerant cycle, oil
lubrication will be insufficient and compressor burnout may
occur, so take care to avoid this.
2. DO NOT OPEN HIGH PRESSURE VALVE OF MANIFOLD GAUGE WITH COMPRESSOR OPERATING
If the high pressure valve is opened, refrigerant flows in the
reverse direction and could cause the charging cylinder to
rupture, so open and close the low pressure valve only.
3. BE CAREFUL NOT TO OVERCHARGE WITH REFRIGERANT IN SYSTEM
If refrigerant is overcharged, it causes trouble such as insuffi-
cient cooling, poor fuel economy, engine overheating etc.
Electrical Parts
Before removing and inspecting the electrical parts, set the
ignition switch to the LOCK position and disconnect the neg-
ative (±) terminal cable from the battery.
CAUTION: Work must not be started until after at least 20
seconds or longer from the time the negative (±) terminal
cable is disconnected.
SRS Airbag System
Failure to carry out service operations in the correct se-
quence could cause the airbag system to deploy, possibly
leading to a serious accident.
When removal or installation of the parts and the yellow wire
harness and connector for the airbag is necessary, refer to
the precautionary notices in the AB section before perform-
ing the operation.
±
AIR CONDITIONING SYSTEM General DescriptionAC±5
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DESCRIPTION
The combination meter has various meters and gauges which show the vehicle'\
s condition, warning lights which
monitor abnormalities in the vehicle and inform the driver, indicator lights which inform the driver of the condition
of each part of vehicle, and a function for illumination and brightness ad\
justment of meters and gauges.
The component parts of this system and their functions are described in \
the following table.
Parts NameFunction
SpeedometerThe speedometer needle moves in accordance with signals from the speed s\
ensor to
indicate the vehicle's speed.
TachometerThe tachometer needle moves in accordance with signals from the igniter \
to indicate the
engine's speed.
Water Temperatrue
GaugeThe water temperature gauge's needle moves in accordance with signals from the send-
er gauge and indicates the temperature of the engine coolant.
Fuel GaugeThe fuel gauge needle moves in accordance with signals from the sender g\
auge, indicat-
ing the amount of fuel remaining in the fuel tank.
OdometerThe odometer counts the total distance traveled by the vehicle in accord\
ance with pulse
signals from the speed sensor.
Twin Trip Switch
The twin trip meter counts the distance traveled by the vehicle in accor\
dance with pulse
signals from the speed sensor. It can be reset using a switch and can be used to switch
between trip meters A and B.
Circuit Plate
This plate contains the circuitry for each meter and gauge and for each \
warning light and
indicator light, as well as an internal engine oil level warning drive c\
ircuit, drive circuits for
the odometer and trip meter and brightness adjustment circuitry for each\
indicator.
Speed SensorMounted in the transmission, this sensor outputs pulse signals to the co\
mbination meter
in accordance with the speed of the output shaft.
Twin Trip SwitchOperation of this switch switches between the A and B trip meters and se\
nds reset sig-
nals to the combination meter.
Water
Temperature Sender
GaugeThis sender converts engine coolant temperatures to a resistance value i\
n signal form to
the combination meter.
Fuel Sender GaugeThis sender converts the level of fuel remaining in fuel tank to resista\
nce value and
sends the resistance value in signal form to combination meter.
Rheostat Light
Control VolumeIn order to adjust the degree of illumination of the combination meter, the resistance val-
ue of the built±in variable resistor is sent to the combination meter\
and rheostat light
control.
Fuel Level Warning
SwitchWhen the level of fuel remaining falls below a predetermined level, cont\
inuity is estab-
lished with this switch, which is built into the fuel sender gauge, caus\
ing a warning light
to light up.
Low Oil Pressure
Warning SwitchThis switch is mounted on the engine block. Continuity is established in\
this switch when
the oil pressure is low, causing a warning light to light up.
Integration Relay (Seat
Belt Warning Relay)
This relay receives current from fuse GAUGE and DOME and is connected to\
each
buckle switch, door courtesy switch, key unlock warning switch and warni\
ng light. As
part of the seat belt warning system, it sounds a chime and lights a war\
ning light when
seat belts are unfastened. As part of the key unlock warning system, it \
sounds a chime
when the set conditions are fulfilled.
Light Failure SensorThis sensor senses when a bulb in rear combination light is burnt out an\
d lights up a
warning light.
BE±96±
BODY ELECTRICAL SYSTEM Combination Meter
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ConnectionCheck forTester connectionConditionSpecified value
A19 A15Trip switch A/BPushContinuity
Trip switchContinuity
A19±A15Trip switch A/BFreeNo continuityTrip switchContinuity
A20 A15Trip switch RESETPushContinuityA20±A15Trip switch RESETFreeNo continuity
DOME
FuseVoltageA11±GroundConstantBattery positive voltage
Speed
SVoltageA13 A15
Ignition
switch
*3 Revolve propeller shaft0V
11 V
SensorVoltageA13±A15switch
ON*3 Stop propeller shaft0V or 11V
C1±GroundPBattery positive voltage
C2±GroundIgnitionRBattery positive voltage
Neutral start
it hVoltageC3±Ground
Ignition
switch
ON andNBattery positive voltageswitchVoltageC4±GroundON and
shift leverDBattery positive voltage
C5±Ground
shift lever
position2Battery positive voltage
C16±Ground
osition
LBattery positive voltage
O/D OFFContinuityC18 GroundO/D OFF switchONContinuity
SwitchContinuityC18±GroundO/D OFF switchOFFNo continuity
AlternatorContinuityC15±GroundEngine stopContinuity
ºLº terminalVoltageC14±GroundEngine runningBattery positive voltage
FuelContinuityA7 GroundFuel remainderFullNo continuity
SenderContinuityA7±GroundFuel remainderEmptyContinuity
GaugeFull, Approx. 79.3 mm
(3.12 in.)Approx. 6

ResistanceA8±C8Float
position1/2, Approx. 193.1 mm
(76.0 in.)Approx. 32.5

Empty, Approx. 308.1 mm
(12.13 in.)Approx. 97

*Window
washer level
ContinuityB9±GroundON (float down)Continuitywasher level
warning
switchContinuityB9 Ground
(Canada)OFF (float up)No continuity
Brake fluidBrake fluid levelON (float down)Continuity
Level warning
Brake fluid level
warning SWOFF (float up)No continuity
SW and
Parking brake
SW
ContinuityC13±GroundParking brake
ON (Depress the Ped-
al))Continuity
SWParking brake
SWOFF (Release the Ped-
al)No continuity
Low oil
PressureContinuityC19 GroundEngine condition
RunningNo continuity
Pressure
Warning SWContinuityC19±GroundEngine conditionStopContinuity
Door courtesyContinuityC12 GroundDriver's andOpen (ON)Continuityy
SwitchContinuityC12±GroundDriver s and
passenger's doorClosed (OFF)No continuity
IGN fuseVoltageC14 GroundIgnition switchONBattery positive voltageVoltageC14±GroundIgnition switchLOCK or ACCNo voltage
CIG fuseVoltageA6 GroundIgnition switchACC or ONBattery positive voltageVoltageA6±GroundIgnition switchLOCK or STARTNo voltage
BE±107±
BODY ELECTRICAL SYSTEM Combination Meter
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11. INSTALL LH ENGINE WIRE COVER(a) Connect portions A and B engine wire cover to the wirebrackets.
(b) Set the VSV (for fuel pressure control system) wire in
original position.
(c) Fit portions C and D of the engine wire cover, matching them with the lower high±tension cord cover and No.3
timing belt cover.
(d) Install the engine wire cover with the two bolts.
12. INSTALL UPPER HIGH±TENSION CORD COVER (a) Fit portion A of the upper high±tension cover, matchingit with the top of the lower high±tension cord cover.
(b) Push the front side of the high±tension cord cover, and connect 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
CO±44
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Pump)
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3. VISUALLY INSPECT FUEL TANK CAPCheck if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
INSPECTION OF CHARCOAL CANISTER
1. REMOVE CHARCOAL CANISTER(a) Disconnect the following hoses:(1) Vacuum hose (from VSV) from charcoal canister
(2) EVAP hose from charcoal canister
(b) Disconnect the grommet on the check valve from the bracket, and remove the charcoal canister.
(c) Remove the check valve from the hose end on the charcoal canister.
2. VISUALLY INSPECT CHARCOAL CANISTER Look for cracks or damage.
3. CHECK FOR CLOGGED FILTER AND STUCK CHECK VA LV E
(a) Using low pressure compressed air, blow into port A and
check that air flows without resistance from the other
ports.
(b) Blow into port B and check that air does not flow from the
other ports.
If a problem is found, replace the charcoal canister.
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EMISSION CONTROL SYSTEMS Fuel Evaporative Emission Control (EVAP) SystemEC±9
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Front water bypass joint x Cylinder head  18 185 13
 Intake manifold x Cylinder head1818513
Delivery pipe x Intake manifold1818513 
Fuel return pipe x Fuel pressure regulator
  
35
 
360
 
26 Fuel inlet hose x Delivery pipe  39 400 29  for SST 33 340 24 Cold start injector x Air intake chamber  7.8 80 69 in.Vlbf Air intake chamber x Intake manifold  18 185 13 EGR pipe x Air intake chamber  18 185 13
 EGR pipe x RH cylinder head  18 185 13
 Cold start injector tube x Air intake chamber  15 150 11
 Union (for brake booster) x Air intake chamber  29 300 22
 Throttle body x Air intake chamber  18 185 13
 IAC valve x Air intake chamber  18 185 13
 EGR valve adaptor x Air intake chamber  18 185 13
 EGR valve x EGR valve adaptor  18 185 13
Timing belt rear plate x Cylinder head7.88069 in. Vlbf 
Water outlet housing x Water pump
  
18
 
185
 
13 Main bearing stud bolt x Cylinder block  15 150 11 Main bearing cap x Cylinder block for nut (1st) 27 275 20  (2nd) Turn 90 5  
  for bolt 49 500 36 Connecting rod cap x Connecting rod 1st 25 250 18
  2nd Turn 905  
 Rear oil seal retainer x Cylinder block  7.8 80 69 in.Vlbf
 Water seal plate x Cylinder block  14 145 10
 Generator bracket x Cylinder block  18 185 13
 Oil pump x Cylinder block 12 mm head 16 160 12
  14 mm head 30 310 22
 No.1 oil pan x Cylinder block 10 mm head 7.8 80 69 in. Vlbf
12 mm head1818513 
No.1 oil pan x Oil pump
  
7.8
 
80
 
69 in. Vlbf No.1 oil pan x Rear oil seal retainer  7.8 80 69 in. Vlbf Oil strainer x Cylinder block  7.8 80 69 in. Vlbf Oil strainer x Oil pump  7.8 80 69 in. Vlbf Oil pan baffle plate x No.1 oil pan  7.8 80 69 in. Vlbf No.1 oil pan x No.2 oil pan  7.8 80 69 in. Vlbf
 Water pump x Cylinder block  18 185 13
 Water bypass pipe x Cylinder Block  18 185 13
 Knock sensor x Cylinder block  44 450 33
 Starter x Cylinder block  39 400 29
 Engine mounting bracket x Cylinder block  37 380 27
 Drive plate x Crankshaft  98 1,000 72
 Transmission x Cylinder block  57 580 42
 Transmission x No.1 oil pan  39 400 29
Drive plate x Torque converter3334025 Transmission oil cooler pipe x Transmission for union nut 34 350 25 Rear engine mounting member x Body  25 250 19\
 \
Rear engine mounting member x Rear engine mounting insulator1313510
EG±210±
1UZ ± FE ENGINE ENGINE MECHANICAL
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31. RECONNECT FUEL INLET HOSE TO LH DELIVERY PIPE
(a) Temporarily connect the fuel inlet hose to the delivery pipewith 2 new gaskets and pulsation damper.
(b) Using SST, tighten the pulsation damper.
SST 09631±22020
Torque:
39 NVm (400 kgf Vcm, 29 ft Vlbf)
33 N Vm (340 kgf Vcm, 24 ft Vlbf) for SST
HINT: Use a torque wrench with a fulcrum length of 30 cm
(11.81 in.).
32. RECONNECT FUEL RETURN HOSE TO FUEL RETURN PIPE
33. RECONNECT PCV HOSE TO LH CYLINDER HEAD
34. REINSTALL RH ENGINE WIRE COVER
(a) Fit portions A and B of the engine wire cover, matching them with the lower high±tension cord cover and No.3 timing belt
cover.
(b) Install the timing belt cover with the bolt.
35. REINSTALL LH ENGINE WIRE COVER
(a) Connect portions A and B of the engine wire cover to the wire
brackets.
(b) Set the VSV (for the fuel pressure) wire in original position.
(c) Fit portions C and D of the engine wire cover, matching them with the lower high±tension cord cover and No.3 timing belt
cover.
(d) Install the timing belt cover with the 2 bolts.
36. REINSTALL UPPER HIGH±TENSION CORD COVER
(a) Fit portion A of the upper high±tension cord cover matching the top of the lower high±tension cord cover.
EG±30
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1UZ±FE ENGINE ENGINE MECHANICAL
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