Lexus SC300 / Lexus SC400. Service manual — part 509

INSTALLATION OF FUEL PUMP

(See Components on page

FI–19

)

1.

INSTALL FUEL PUMP
(a) Install a new gasket to the pump set plate.
(b) Connect the fuel hose to the fuel pump bracket, and

install the fuel pump and bracket assembly with the
three nuts.

Torque: 5.4 N

⋅

m (55 kgf

⋅

cm, 48 in.

⋅

lbf)

(b) Install the fuel pump set plate with the eight bolts.

Torque: 3.9 N

⋅

m (40 kgf

⋅

cm, 35 in.

⋅

lbf)

2. INSTALL

PARTITION

COVER

Install the partition cover with butyl tape.

3.

INSTALL SEAT BACK AND CUSHION

4.

CONNECT FUEL PUMP CONNECTOR

5.

INSTALL LUGGAGE COMPARTMENT TRIM COVER

6.

INSTALL SPARE TIRE

7.

INSTALL LUGGAGE COMPARTMENT FLOOR MAT

8. CONNECT CABLE TO NEGATIVE TERMINAL OF

BATTERY

9.

START ENGINE, AND CHECK FOR FUEL LEAKS

–

EFI SYSTEM

Fuel System (Fuel Pump)

FI–23

FUEL SYSTEM
Fuel Pump

ON–VEHICLE INSPECTION

1.

CHECK FUEL PUMP OPERATION
(a) Using SST, connect terminals +B and FP of the check

(”DIAGNOSIS”) 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

If there is no pressure, check the following parts:

•

Fuses

•

EFI main relay

•

Fuel pump ECU

•

Fuel pump

•

Engine & ECT ECU

•

Wiring connections

2.

CHECK FUEL PRESSURE
(a) Check the battery voltage above 12 volts.
(b) Disconnect the cable from the negative (–) terminal of

the battery.

CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ”LOCK” 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:

•

Put a suitable container or shop towel under the cold
start injector pipe.

•

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

⋅

m (400 kgf

⋅

cm, 29 ft

⋅

lbf)

(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

(”DIAGNOSIS”) connector.

SST 09843–18020
(i)

Reconnect the cable to the negative (–) terminal of the
battery.

FI–18

EFI SYSTEM – Fuel System (Fuel Pump)

(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:

•

Fuel hoses and connections

•

Fuel pump

•

Fuel filter

•

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) Reconnect 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 remains

147 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

⋅

m (400 kgf

⋅

cm, 29 ft

⋅

lbf)

(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)