Lexus RX300 (MCU15). Service manual - part 408

B00347

B00061

New O–ring

CORRECT

WRONG

Delivery Pipe

Injector

B05295

Delivery Pipe

Grommet

O–Ring

Grommet

Spacer

O–Ring

B12940

Fuel Hose
Clamp

B12941

A

A

–

ELECTRONIC FUEL INJECTION

EFI SYSTEM

FI–3

LEXUS RX300   (RM785E)

(6)

Put a container under the connection.

(b)

Observe these precautions when removing and installing
the injectors.
(1)

Never reuse the O–ring.

(2)

When placing a new O–ring on the injector, take
care not to damage it in any way.

(3)

Coat a new O–ring with spindle oil or gasoline be-
fore installing–never use engine, gear or brake oil.

(c)

Install the injector to the delivery pipe and intake manifold,
as shown in the illustration.
Before installing the injector, must apply spindle oil or gas-
oline on the place where a delivery pipe or an intake man-
ifold touches an O–ring of the injector.

(d)

Observe these precautions when disconnecting the fuel
tube connector.
(1)

Remove the fuel pipe clamp.

(2)

Check if there is any dirt like mud on the pipe and
around the connector before disconnecting them
and clean the dirt away.

(3)

Disconnect the connector from the hose while
pinching part A with fingers as shown in the illustra-
tion.

B12944

B09222

Vinyl Bag

D09456

Hand–Held Tester

DLC3

FI–4

–

ELECTRONIC FUEL INJECTION

EFI SYSTEM

LEXUS RX300   (RM785E)

HINT:
When the connector and the pipe are stuck, pinch the fuel pipe
between the hands, push and pull the connector to free to dis-
connect and pull it out. Do not use any tool at this time.

(4)

Inspect if there is any dirt or the likes on the seal sur-
face of the disconnected pipe and clean it away.

(5)

Prevent the disconnected pipe and connector from
damaging and mixing foreign objects by covering
them with a vinyl bag.

(e)

Check that there are no fuel leaks after doing mainte-
nance anywhere on the fuel system.
(1)

Connect the hand–held tester to the DLC3.

(2)

Turn the ignition switch ON and push hand–held
tester main switch ON.

NOTICE:
 Do not start the engine.

(3)

Select the active test mode on the hand–held tester.

(4)

Please refer to the hand–held tester operator’s
manual for further details.

(5)

If you have no hand–held tester, connect the posi-
tive (+) and negative (–) leads from the battery to the
fuel pump connector.(See page FI–5)

(6)

Check that there are no leaks from any part of the
fuel system.

(7)

Turn the ignition switch to LOCK.

(8)

Disconnect the hand–held tester from the
DLC3.

D09456

Hand–Held Tester

DLC3

FI0UP–01

B12942

B09225

Fuel Tube Connector

–

ELECTRONIC FUEL INJECTION

FUEL PUMP

FI–5

LEXUS RX300   (RM785E)

FUEL PUMP

ON–VEHICLE INSPECTION

1.

CHECK FUEL PUMP OPERATION

(a)

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch ON and hand–held tester main
switch ON.

NOTICE:
Do not start the engine.
(c)

Select the active test mode on the hand–held tester.

(d)

Please refer to the hand–held tester operator’s manual
for further details.

(e)

If you have no hand–held tester, connect the positive (+)
and negative (–) leads from the battery to the fuel pump
connector. (See step 7)

(f)

Check that there is pressure in the fuel inlet pipe from the
fuel filter.

HINT:
If there is fuel pressure, you will hear the sound of fuel flowing.
If there is no pressure, check the fusible link, fuses (AM2 30A,
IGN 5A), EFI main relay, fuel pump and wiring connections.
(g)

Turn the ignition switch to LOCK.

(h)

Disconnect the hand–held tester from the DLC3.

2.

CHECK FUEL PRESSURE

(a)

Check the battery positive voltage is above 12 V.

(b)

Disconnect the negative (–) terminal cable from the bat-
tery.

(c)

Purchase the new No.1 fuel pipe and take out the fuel
tube connector from its pipe.
Part No. 23801–20040

B12940

Fuel 
Hose
Clamp

B12941

B12975

No.1 Fuel
Pipe

SST

Fuel Tube
Connector

SST
(Hose)

SST
(Hose)

SST
(Hose)

FI–6

–

ELECTRONIC FUEL INJECTION

FUEL PUMP

LEXUS RX300   (RM785E)

(d)

Remove the fuel hose clamp.

(e)

Disconnect the No.1 fuel pipe (fuel tube connector) from
the fuel filter outlet.

CAUTION:

S

Perform disconnecting operations of the fuel tube
connector (quick type) after observing the precau-
tions.

S

As there is retained pressure in the fuel pipe line, pre-
vent it from splashing inside the engine compart-
ment.

(f)

Install SST (pressure gauge) as shown in the illustration
by using SST and fuel tube connector.
SST

09268–41047, 09268–41250, 09268–45012

(g)

Wipe off any splattered gasoline.

(h)

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

(i)

Connect the hand–held tester to the DLC3.
(See step 1.)

(j)

Measure the fuel pressure.
Fuel pressure:
301 – 347 kPa (3.1 – 3.5 kgf/cm

2

, 44 – 50 psi)

If pressure is high, replace the fuel pressure regulator.
If pressure is low, check the fuel hoses and connections, fuel
pump, fuel filter and fuel pressure regulator.
(k)

Disconnect the hand–held tester from the DLC3.

(l)

Start the engine.

(m)

Measure the fuel pressure at idle.
Fuel pressure:
301 – 347 kPa (3.1 – 3.5 kgf/cm

2

, 44 – 50 psi)

(n)

Stop the engine.

(o)

Check that the fuel pressure remains as specified for 5
minutes after the engine has stopped.
Fuel pressure: 147 kPa (1.5 kgf/cm

2

, 21 psi) or more

If pressure is not as specified, check the fuel pump, pressure
regulator and/or injectors.
(p)

After checking fuel pressure, disconnect the negative (–)
terminal cable from the battery and carefully remove the
SST and fuel tube connector to prevent gasoline from
splashing.
SST

09268–41047,  09268–41250, 09268–45012