1991 LEXUS SC300 fuel filter

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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FUEL SYSTEM
Fuel is pumped up by the fuel pump, which flows through the fuel filter unde\
r pressure through the fuel pipe
to the delivery pipe where it is distributed to each injector. The fuel pressure regulator adjusts the pressure of the fuel from the fuel \
line (high pressure side) to a pressure
284 kPa (2.9 kgf/cm2, 41 psi) higher than the pressure inside the intake \
manifold, and excess fuel is returned
to the fuel tank through the return pipe.
When the engine is hot, the fuel pressure is increased to control percolation in the fuel system and impr\
ove
restartability and idling stability.
The pulsation damper absorbs the slight fluctuations in fuel pressure ca\
used by the injector.
The injectors operate on input of injection signals from the ECU and inj\
ect fuel into the intake manifold.
FI±6
±
EFI SYSTEM Operation
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FUEL SYSTEM
Fuel is pumped up by the fuel pump, which flows through the fuel filter under pr\
essure through the fuel pipe
to the delivery pipe where it is distributed to each injector and the cold\
start injector.
The fuel pressure regulator adjusts the pressure of the fuel from the fuel \
line (high pressure side) to a pres-
sure 284 kPa (2.9 kgf/cm
2, 41 psi) higher than the pressure inside the intake manifold, and exce\
ss fuel is re-
turned to the fuel tank through the return pipe.
When the engine is hot, the fuel pressure is increased to control percolatio\
n in the fuel system and improve
restartability and idling stability.
The pulsation damper absorbs the slight fluctuations in fuel pressure ca\
used by the injector.
The injectors operate on input of injection signals from the ECU and inj\
ect fuel into the intake manifold.
The cold start injector operates when starting with low coolant temperature or at normal temperature
ranges, injecting fuel into the air intake chamber to improve startability. FI±7
EFI SYSTEM
± Operation
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FUEL SYSTEM
Fuel Pump
ON±VEHICLE INSPECTION
1. CHECK FUEL PUMP OPERATION(a) Using SST, connect terminals +B and FP of the check
(ºDIAGNOSISº) connector.
SST 09843±18020
(b) Turn the ignition switch ON.
NOTICE: Do not start the engine.
(c) Check that there is pressure in the fuel inlet hose from the fuel filter.
HINT: At this time, you will hear fuel return noise.
(d) Turn the ignition switch OFF.
(e) Remove SST from the check connector.
SST 09843±18020
FI±16
±
EFI SYSTEM Fuel System (Fuel Pump)
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(h) Turn the ignition switch ON.
(i) Measure the fuel pressure.
Fuel pressure: 265±304 kPa (2.7±3.1 kgf/cm, 38±44 psi)
If pressure is high, replace the fuel pressure regulator.
If pressure is low, check the following parts:w Fuel hoses and connections
w Fuel pump
w Fuel filter
w Fuel pressure regulator
(j) Remove SST from the check connector.
SST 09843±18020
(k) Start the engine.
(l) Disconnect the vacuum sensing hose from the fuel pressure regulator, and plug the hose end.
(m) Measure the fuel pressure at idle.
Fuel pressure: 265±304 kPa
(2.7±3.1 kgf/cm, 38±44 psi)
(n) Re c onnect the vacuum sensing hose to the fuel
pressure regulator.
(o) Measure the fuel pressure at idle.
Fuel pressure: 196±235 kPa
(2.0±2.4 kgf/cm, 28±34 psi)
If pressure is not as specified, check the vacuum sensing
hose and fuel pressure regulator.
(p) Stop the engine. Check that the fuel pressure remains147 kPa (1.5 kgf/cm2, 21 psi) or more for 5 minutes after
the engine is turned off.
If pressure is not as specified, check the fuel pump, pressure
regulator and/or injectors.
(q) After checking fuel pressure, disconnect the battery
negative (±) cable and carefully remove SST to prevent
gasoline from splashing.
SST 09268±45012
(r) Connect the No. 1 fuel pipe to the delivery pipe with two new gaskets and the union bolt.
Torque: 42 N Vm (420 kgf Vcm, 30 ft Vlbf)
(s) Reconnect the cable to the negative (±) terminal of the
battery.
(t) Check for fuel leaks. (See page FI±15)
FI±18
±
EFI SYSTEM Fuel System (Fuel Pump)
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DISASSEMBLY OF FUEL PUMP
(See Components on page FI±21)
1. REMOVE PUMP SET PLATE FROM FUEL PUMP Disconnect the lead connector from the fuel pump, and re-
move the set plate.
2. REMOVE FUEL PUMP FROM PUMP BRACKET (a) Pull out the lower side of the fuel pump from the pumpbracket.
(b) Remove the rubber cushion from the fuel pump.
(c) Disc onnect the fuel hose from the fuel pump, and
remove the fuel pump.
3. REMOVE FUEL PUMP FILTER FROM FUEL PUMP (a) Using a small screwdriver, remove the clip.
(b) Pull out the pump filter.
ASSEMBLY OF FUEL PUMP
(See Components on page FI±21)
1. INSTALL FUEL PUMP FILTER TO FUEL PUMP
Install the pump filter with a new clip.
2. INSTALL FUEL PUMP TO FUEL PUMP BRACKET (a) Connect the fuel hose to the outlet port of the fuel pump.
(b) Install the rubber cushion to the fuel pump.
(c) Install the fuel pump by pushing the lower side of the fuel
pump.
3. INSTALL PUMP SET PLATE TO FUEL PUMP Connect the lead connector on the set plate to the fuel pump.
FI±22
±
EFI SYSTEM Fuel System (Fuel Pump)
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FUEL SYSTEM
Fuel Pump
ON±VEHICLE INSPECTION
1. CHECK FUEL PUMP OPERATION(a) Using SST, connect terminals +B and FP of the check
(ºDIAGNOSISº) connector.
SST 09843±18020
(b) Turn the ignition switch ON.
NOTICE: Do not start the engine.
(c) Check that there is pressure in the fuel inlet hose from the fuel filter.
HINT: At this time, you will hear fuel return noise.
(d) Turn the ignition switch OFF.
(e) Remove SST from the check connector.
SST 09843±18020 FI±17
± Fuel System (Fuel Pump)EFI SYSTEM
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If there is no pressure, check the following parts:w Fuses
w EFI main relay
w Fuel pump ECU
w Fuel pump
w Engine & ECT ECU
w Wiring connections
2. CHECK FUEL PRESSURE (a) Check the battery voltage above 12 volts.
(b) Disconnect the cable from the negative (±) terminal ofthe battery.
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 negative (±) terminal
cable is disconnected from the battery.
(c) (Exc. USA Spec.) Remove the filter from the VSV (for EGR system).
(d) Remove the union bolt holding the LH deliver pipe to the
rear fuel pipe. Remove the two gaskets.
HINT:
w Put a suitable container or shop towel under the cold
start injector pipe.
w Slowly loosen the union bolt.
(e) Install the rear fuel pipe and SST (pressure gauge) to the LH delivery pipe with three new gaskets and the
union bolt.
SST 09268±45012
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
(f) Wipe off any splattered gasoline.
(g) (Exc. USA Spec.)
Reinstall the filter to the VSV.
(h) Using SST, connect terminals B and FP of the check (ºDIAGNOSISº) connector.
SST 09843±18020
(i) Reconnect the cable to the negative (±) terminal of the
battery.
FI±18
EFI SYSTEM
± Fuel System (Fuel Pump)
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