Lexus RX300 (MCU15). Service manual - part 416

FI0V9–01

A05687

B04794

Throttle
Position
Sensor
Connector

B04795

(c)

(e)

(d)

(f)

ISC
Valve
Connector

B04793

–

ELECTRONIC FUEL INJECTION

THROTTLE BODY

FI–35

LEXUS RX300   (RM785E)

REMOVAL

1.

DRAIN ENGINE COOLANT

2.

DISCONNECT ACCELERATOR CABLE

3.

DISCONNECT THROTTLE CABLE

4.

REMOVE AIR CLEANER HOSE

(a)

Disconnect the PCV hose.

(b)

Loosen the 2 hose clamps, and remove the air cleaner
hose.

5.

REMOVE THROTTLE BODY

(a)

Disconnect the throttle position sensor connector.

(b)

Disconnect the ISC valve connector.

(c)

Disconnect the water bypass hosese.

(d)

Disconnect the air assist hose.

(e)

Disconnect the 2 fuel vapor feed hosese.

(f)

Disconnect the vacuum hose.

(g)

Remove the 3 nuts,throttle body and gasket.

HINT:
At the time of installation, please refer to the following items.
Place a new gasket on the air intake chamber.

Torque: 19.5 N·m (200 kgf·cm, 14 ft·lbf)

FI0VA–01

B05129

Must Have 
No Clearance

Must Have 
Clearance

B05130

Throttle Stop Screw

Adjust Screw
(Close Side)

Adjust Screw
(Open Side)

B05131

Close Side

Open Side

B05132

Fully Opening

Thickness
Gauge

(Close Side)

Adjust Screw

FI–36

–

ELECTRONIC FUEL INJECTION

THROTTLE BODY

LEXUS RX300   (RM785E)

INSPECTION

NOTICE:
In case of changing, removing or installing the throttle
body or ISC valve, must do this.
1.

THROTTLE BODY INSPECTION

(a)

Check that there is no clearance between each throttle
stop screw and the throttle lever when applying the nega-
tive pressure (53.3 kPa (400 mmHg)) to the throttle open-
er using the MITYVAC.

Standard: Must have no clearance.

NOTICE:
As the throttle stop screw is precisely adjusted, so do not
adjust it.

(b)

Under the condition of (1), check visually that there is a
clearance between each adjust screw and the throttle le-
ver on No. 1 side.

Adjust Screw

Reference Value

Close Side

About 0.13 mm

Open Side

About 0.22 mm

(c)

Measure the clearance between the adjust screw on the
close side when fully opening the throttle lever on No. 2
side by hand and the throttle lever on No. 1 side with a
thickness gauge.
Standard value: 0.25 – 0.45 mm
In case of being out of standard value, perform the ad-
justment of (2).

B05133

Throttle Stop Screw

Adjust Screw
(Close Side)

Adjust Screw
(Open Side)

B05184

Close Side

Open Side

–

ELECTRONIC FUEL INJECTION

THROTTLE BODY

FI–37

LEXUS RX300   (RM785E)

2.

THROTTLE BODY (BALANCE) ADJUSTMENT

NOTICE:
Do not adjust the throttle stop screw and throttle opener.
(a)

Beforehand checking
Recheck 1 – (1)

(b)

Adjustment of the adjust screw on the open side
(1)

Loosen the lock nut and screw using the hexagon
wrench (width of two planes 2 mm), make clearance
between the screw tip and the throttle lever on No.
1 side.

(2)

Turn the screw to the screw torque direction gradu-
ally, and stop it at the position where to touch the le-
ver at the very moment.

NOTICE:
If turning it too much to the torque direction, No. 1 lever
goes off from the throttle stop screw causing the adjust-
ment failure.

(3)

Turn it back from the position where it touches the
lever to the screw loosing direction.

Standard:
Turn it back by rotating 1/4.
(4)

Torque the lock nut.

(c)

Adjustment of the adjust screw on the close side
(1)

Loosen the lock nut and screw, and make clearance
between the screw tip and the throttle lever on No.
1 side.

(2)

Turn the screw to the screw torque direction gradu-
ally, and stop it at the position where to touch the le-
ver at the very moment.

NOTICE:
If turning it too much to the torque direction. No. 2 lever
goes off from the throttle stop screw causing the adjust-
ment failure.

(3)

Turn it back from the position where it touches the
lever to the screw loosing direction.

Standard:
Turn it back by rotating 1/2 – 3/4.
(4)

Torque the lock nut.

(d)

Completion checking
Check 1 – (3).

FI0VB–01

B05127

B05128

Gasket

O–Ring

Gasket

O–Ring

FI–38

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ELECTRONIC FUEL INJECTION

THROTTLE BODY

LEXUS RX300   (RM785E)

INSTALLATION

NOTICE:

S

Do not give a shock to the throttle position senor.

S

Do not disassemble or adjust the throttle opener.

1.

INSTALLATION OF THE THROTTLE POSITION SEN-
SOR

Installation is in the reverse order of removal
(See page FI–35).
(a)

Check that the throttle valve is fully open.

(b)

Insert the sensor to the throttle body with it turned clock-
wise by 30 to 60° against the fully – open valve position.

(c)

By turning the sensor counterclockwise, torque the sen-
sor.

2.

INSTALLATION OF THE THROTTLE BODY NO. 1 AND
NO. 2

Set the gasket and O–ring as shown in the illustration to the il-
lustration to the lift.