1991 LEXUS SC400 fuel pressure

INSTALLATION OF FUEL PRESSURE
PULSATION DAMPER
(See Components on page FI±58)
1. INSTALL FUEL PRESSURE PULSATION DAMPER Using SST, install two new gaskets, the inlet hose and pulsa-
tion damper.
SST 09612±24014 (09617±24011)
Torque: 39 N Vm (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.)
2. 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.
3. INSTALL UPPER HIGH±TENSION CORD COVER (a) Fit portion A of the upper high±tension cover, matching
it 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.
4. CONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
5. CHECK FOR FUEL LEAKS (See page FI±16)
FI±60
EFI SYSTEM
± Fuel System (Fuel Pressure Pulsation Damper)
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COMPONENTS
REMOVAL OF ISC VALVE
1. REMOVE LOWER HIGH±TENSION CORD COVER(See steps 1, 2 and 5 to 12 on pages FI±27 to 29)
2. REMOVE ISC VALVE
(a) Disconnect the ISC valve connector.
(b) (USA Spec.)Remove the bolt holding the water by±pass pipe (be-
tween ISC valve and EGR valve) to the air intake cham-
ber.
(c) (Exc. USA Spec.) Remove the bolt holding the water by±pass pipe (be-
tween ISC valve and EGR valve) to the VSV (for fuel
pressure control). FI±81
EFI SYSTEM
± Air Induction System (Idle Speed Control (ISC) Valve)
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INSTALLATION OF ISC VALVE
(See Components on page FI±81)
1. INSTALL ISC VALVE (a) Install a new gasket and the ISC valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(b) Connect the following hoses to the ISC valve:
(1) Water by±pass hose (from throttle valve)
(2) Water by±pass hose (from water inlet housing)
(3) Water by±pass hose (from EGR valve)
(c) (USA Spec.) Install the vacuum pipe and water by±pass pipe (be-
tween ISC valve and EGR valve) to the air intake cham-
ber with the bolt.
(d) (Exc. USA Spec.) Install the water by±pass pipe (between ISC valve and
EGR valve) to the VSV (for fuel pressure control) with
the bolt.
(e) Connect the ISC valve connector.
1. INSTALL LOWER HIGH±TENSION CORD COVER (See steps 5 to 13 and 16 to 18 on pages FI±39 to 41)FI±83
EFI SYSTEM
± Air Induction System (Idle Speed Control (ISC) Valve)
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VSV for Fuel Pressure Control
FI±90 ± Electronic Control System (VSV for Fue\
l Pressure Control)EFI SYSTEM
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COMPONENTS FOR REMOVAL AND INSTALLATION
FI±91EFI SYSTEM ± Electronic Control System (VSV for Fuel Pressure Control)
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INSPECTION OF VSV FOR FUEL
PRESSURE CONTROL
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 VSV (a) Disconnect the VSV connector.
(b) Disconnect the following hoses from VSV:(1) Vacuum hose (from fuel pressure regulator)
(2) Vacuum hose (from air intake chamber)
(c) (Exc. USA Spec.) Remove the bolt holding the water by±pass pipe to the
VSV.
(d) Remove the bolt and VSV.
FI±92
EFI SYSTEM
± Electronic Control System (VSV for Fuel Pressure Control)
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3. INSPECT VSV
A. Inspect VSV for open circuitUsing an ohmmeter, check that there is continuity between
the terminals.
Resistance (Cold): 37±44

If there is no continuity, replace the VSV.
B. Inspect VSV for ground Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV.
C. Inspect VSV operation (a) Check that air flows from ports E to G.
(b) Apply battery voltage across the terminals.
(c) Check that air flows from ports E to the filter.
If operation is not as specified, replace the VSV.
4. REINSTALL VSV (a) Install the VSV with the bolt.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
FI±93EFI SYSTEM ± Electronic Control System (VSV for Fuel Pressure Control)
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(b) (Exc. USA Spec.)Install the water by±pass pipe to the VSV with the bolt.
(c) Connect the following hoses to VSV: (1) Vacuum hose (from fuel pressure regulator)
(2) Vacuum hose (from air intake chamber)
(d) Connect the VSV connector.
5. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
FI±94
EFI SYSTEM
± Electronic Control System (VSV for Fuel Pressure Control)
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