Lexus SC300 / Lexus SC400. Manual - part 516

Injectors

ON–VEHICLE INSPECTION

1. INSPECT 

INJECTOR 

OPERATION

Check operation sound from each injector.
(a)  With the engine running or cranking, use a stethescope

to check that there is  normal operating  noise in
proportion to engine rpm.

(b)  If you have no stethescope, you can check the injector

transmission operation with your finger.

If no sound or an unusual sound is heard, check the wiring
connector, injector or injection signal from the ECU.

2. INSPECT 

INJECTOR 

RESISTANCE

(a)  Disconnect the injector connector.
(b)  Using an ohmmeter, measure the resistance between

the terminals.

Resistance:     13.4–14.2 

 at 20

°

C (68

°

F)

If the resistance is not as specified, replace the injector.
(c)  Reconnect the injector connector.

FI–26

–

EFI SYSTEM

Fuel System (Injectors)

COMPONENTS FOR REMOVAL AND
INSTALLATION

–

EFI SYSTEM

Fuel System (Injectors)

FI–27

REMOVAL OF INJECTORS
(See Components on page 

FI–27

 )

1. 

DISCONNECT CABLE FROM NEGATIVE TERMINAL OF
BATTERY
CAUTION: Turn the ignition switch to ”LOCK”.
Disconnect the cable from the negative (–) terminal of the
battery. Wait at least 20 seconds before proceeding with
work.

2. 

DRAIN ENGINE COOLANT

3.  REMOVE THROTTLE BODY WITH INTAKE AIR

CONNECTOR
(See steps 2 to 6 on pages 

EM–10

 and 11)

4. 

DISCONNECT NO.1 FUEL PIPE FROM DELIVERY PIPE
Remove the union bolt and two gaskets, and disconnect the
fuel pipe.
HINT:

•

Put a suitable container or shop towel under the delivery
pipe.

•

Slowly loosen the union bolt.

5. 

DISCONNECT NO. 2 FUEL PIPE FROM FUEL PRESSURE
REGULATOR
Remove the union bolt and two gaskets, and disconnect the
fuel pipe from the pressure regulator.
HINT:

•

Put a suitable container or shop towel under the
pressure regulator.

•

Slowly loosen the union bolt.

6. 

REMOVE AIR INTAKE CHAMBER STAYS
Remove the bolt, nut and intake chamber stay.
Remove the No. 1 and No. 2 stays.

FI–28

–

EFI SYSTEM

Fuel System (Injectors)

7.  DISCONNECT VACUUM SENSING HOSE FROM

PRESSURE REGULATOR

8. DISCONNECT 

INJECTOR 

CONNECTORS

9. 

DISCONNECT CONTROL VALVE ACTUATOR
Remove the two bolts and turn the actuator sideways.
HINT: Wrap the actuator with adhesive tape and attach it to
the intake chamber.
NOTICE: Do not apply any force on the actuator rod and
prevent the rod clip from detaching.

10.  REMOVE DELIVERY PIPE AND INJECTORS

(a)  Remove the three bolts and delivery pipe together with

the six injectors.

NOTICE: Be careful not to drop the injectors when re-
moving the delivery pipe.
(b)  Pull out the six injectors from the delivery pipe.
(c)  Remove the O–ring and grommet from each injector.
(d)  Remove the six insulators and three spacers from the

cylinder head.

–

EFI SYSTEM

Fuel System (Injectors)

FI–29