1991 LEXUS SC300 fuel filter

(j) Turn the ignition switch ON.
(k) Measure the fuel pressure.
Fuel pressure: 265±304 kPa(2.7±3.1 kgf/cm
2, 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
(l) Remove SST from the check connector.
SST 09843±18020
(m) Start the engine.
(n) Disconnect the vacuum sensing hose from the fuel pressure regulator, and plug the hose end.
(o) Measure the fuel pressure at idling.
Fuel pressure: 265±304 kPa
(2.7±3.1 kgf/cm
2, 38±44 psi)
(p) Re connect the vacuum sensing hose to the fuel
pressure regulator.
(q) Measure the fuel pressure at idling.
Fuel pressure: 196±235 kPa
(2.0±2.4 kgf/cm
2, 28±34 psi)
If pressure is not as specified, check the vacuum sensing
hose and fuel pressure regulator.
(r) Stop the engine. Check that the fuel pressure remains147 kPa (1.5 kgf/cm
2, 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.
(s) After checking fuel pressure, disconnect the battery negative (±) cable and carefully remove the SST to
prevent gasoline from splashing.
SST 09268±45012
(t) Connect the rear fuel pipe to the delivery pipe with two new gaskets and the union bolt.
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
(u) (Exc. USA spec.)
Reinstall the filter to the VSV.
(v) Reconnect the cable to the negative (±) terminal of the
battery.
(w) Check for fuel leaks. (See page FI±16) FI±19
EFI SYSTEM
± Fuel System (Fuel Pump)
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DISASSEMBLY OF FUEL PUMP
(See Components on page FI±22)
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±22)
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±23
EFI SYSTEM
± Fuel System (Fuel Pump)
WhereEverybodyKnowsYourName

PRECAUTIONS
1. Always use new gaskets when replacing the fuel tank orcomponent part.
2. Apply the proper torque to all parts tightened.
INSPECTION OF FUEL LINES AND
CONNECTIONS
(a) Inspect the fuel lines and connections for cracks,
leakage or deformation.
(b) Inspect the fuel tank vapor vent system hoses and connections for looseness, kinks or damage.
(c) Inspect the fuel tank for deformation, cra cks, fuel
leakage or tank band looseness.
(d) Check the filter neck for damage or fuel leakage.
(e) Ho se an d tu b e c onnections are as shown in the
illustration.
If a problem is found, repair or replace the parts as necessary.
FI±38
±
EFI SYSTEM REPAIR INSTRUCTIONS
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(d) Clean the filter in the canister.Clean the filter by blowing 294 kPa (3 kgf/cm
2, 43 psi) of com-
pressed air into port A while holding port B closed.
NOTICE:
w Do not attempt to wash the canister.
w No activated carbon should come out.
(e) Reinstall the charcoal canister.
(See Emission Control System on page EG±222)
9. REPLACE GASKET IN FUEL TANK CAP
(a) Remove the old gasket from the tank cap. Do not damage the
cap.
(b) Install a new gasket by hand.
(c) Check the cap for damage or cracks.
(d) Install the cap and check the torque limiter.
10. INSPECT FUEL LINES AND CONNECTIONS Visually check the fuel lines for cracks, leakage, loose con-
nections, deformation or tank band looseness.
11. INSPECT EXHAUST PIPES AND MOUNTINGS Visually check the pipes, hangers and connections for se-
vere corrosion, leaks or damage.
12. ADJUST VALVE CLEARANCE (See Engine Mechanical on page EG±14)
Valve clearance (Cold):
Intake
.15 ± 0.25 mm (0.006 ± 0.010 in.)
Exhaust
.25 ± 0.35 mm (0.010 ± 0.014 in.)
MA±10
±
MAINTENANCE (1UZ ± FE)
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Troubleshooting
If the HC/CO concentration does not comply with regulations,
perform troubleshooting in the order given below.
(a) Check oxygen sensor operation.(See page FI±113)
(b) See the table below for possible cause, and then inspect
and correct the applicable causes if necessary.
 

HC 

CO 

Symptoms\
 

\
Cause
 High Normal Rough idle\
 \
1. Faulty ignitions:
   \
 \

Incorrect timing
   \
 \

Fouled, shorted or improperly gapped plugs
   \
 \

Open or crossed high±tension cords
Ckddiib\

Cracked distributor cap
Ill   \
 \
2. Incorrect valve clearance
3 L k EGR l   \
 \
3. Leaky EGR valve
4L k i k d h l   \
 \
4. Leaky intake and exhaust valves
L k li d   \
 \
5. Leaky cylinders
 High Low Rough idle\
 \
1. Vacuum leaks:
   (Fluctuating HC reading)\
 \

PCV hoses
   \
 \

EGR valve
   \
 \

Intake manifold
Ai i k h b   \
 \

Air intake chamber
Th l b d   \
 \

Throttle body
ISC l\

ISC valve
Bkb li   \
 \

Brake booster line
2L i i ifi   \
 \
2. Lean mixture causing misfire
 High High Rough idle\
 \
1. Clogged air filter g g g
(Black smoke from exhaust)\
 \
gg
2. Faulty EFI systems:   ()\
 \
yy

Faulty pressure regulator
   \
 \

yg

Clogged fuel return line
   \
 \

gg

Defective water temp. sensor
   \
 \

Defective air temp. sensor
   \
 \

Faulty ECU
   \
 \

y

Faulty injectors
\

yj

Faulty cold start injector   \
 \
yj

Faulty throttle position sensor   \
 \

Faulty air flow meter
±
ENGINE MECHANICAL Idle and/or 2,500 rpm HC/CO
Concentration Check MethodEM±29
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TORQUE SPECIFICATIONS
\
 \
Part tightened NVm kgf Vcm ft Vlbf
 No.1 idler pulley X Cylinder block  34 350 25
No.2 idler pulley X Cylinder block3435025 Hydraulic pump X Cylinder block 12 mm head 16 160 12  14 mm head 30 310 22
 Crankshaft pulley X Crankshaft  245 2,500 181
Camshaft timing pulley X Camshaft1081,10080 Timing belt tensioner X Oil pump  26 270 20 Spark plug X Cylinder head  18 180 13
 Drive belt tensioner X Cylinder block  16 160 12
Alternator X Alternator bracket3738027 Alternator X Cylinder block  37 380 27 Distributor housing X Cylinder head  18 185 13
 Distributor rotor X Distributor housing   3.8 39  34 in. Vlbf
Distributor cap X Camshaft timing pulley 3.839 34 in. Vlbf\
 \
RH No.2 timing belt cover X Cylinder block (for 12 mm head) 16 160 12 Drive belt idler pulley X Hydraulic pump  37 380 27
 A/C compressor X Hydraulic pump  49 500 36
A/C compressor X Cylinder block4950036 A/C compressor stay X Oil filter bracket  29 300 22 Exhaust manifold X Cylinder head  39 400 29
 Main oxygen sensor X Exhaust manifold  44 450 33
Cylinder head X Cylinder block1st3940029  2nd Turn 90 5  
 Camshaft bearing cap X Cylinder head  16 160 12
 Cylinder head cover X Cylinder head   5.9 60  52 in. Vlbf
Engine hanger X Cylinder head3738027 EGR pipe X Exhaust manifold  18 185 13 Rear water by±pass joint X Cylinder head  18 185 13
 Front water by±pass joint X Cylinder head  18 185 13
Intake manifold X Cylinder head1818513 Delivery pipe X Intake manifold  18 185 13\
 \
Fuel return pipe X RH delivery pipe(for union bolt) 35 360 26
 Fuel inlet hose X LH delivery pipe  39 400 29
for SST3334024 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 head1818513 Cold start injector tube X RH delivery pipe  15 150 11 Brake booster union X Air intake chamber  29 300 22
 Throttle body X Air intake chamber  18 185 13
ISC valve X Air intake chamber1818513 EGR valve adapter X Air intake chamber  18 185 13 EGR valve X EGR valve adapter  18 185 13
 Timing belt rear plate X Cylinder head   7.8 80  69 in. Vlbf
Water inlet housing X Water pump1818513\
 \
Catalytic converter (main) X Exhaust manifold 62 630 46\
 \
Catalytic converter (main) X Front exhaust pipe 43 440 32
\
 \
Front exhaust pipe support bracket X Transmission 43 440 32
PS pump X RH cylinder headBolt3940029  Nut 43 440 32 Main bearing cap X Cylinder block Nut 1st 27 275 20
  2nd Turn 90 5  
Bolt4950036
±
ENGINE MECHANICAL Service SpecificationsEM±181
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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±17
± Fuel System (Fuel Pump)EFI SYSTEM
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