Lexus SC300 / Lexus SC400. Manual - part 470

INSPECTION OF INJECTORS

1. INSPECT 

INJECTOR 

INJECTION

CAUTION: Keep injector clear of sparks during the test.

(a)  Disconnect the fuel inlet hose from the fuel tube.
(b)  Connect SST (hose) to the fuel inlet tube with SST

(union). Tighten the flare nut on the fuel tube.

SST 09268–41045 (90405–52010)

Torque: 30 N

⋅

m (310 kgf

⋅

cm, 22 ft

⋅

lbf)

HINT: Use SST. (See page 

FI–15

)

SST 09631–22020

(c)  Loosen the lock nut, and remove the pressure regulator

from the RH delivery pipe. Remove the O–ring from the
pressure regulator.

(d)  Install a new O–ring to the fuel inlet of the pressure

regulator.

(e)  Connect SST (hose) to the pressure regulator with SST

(union). Tighten the lock nut on the pressure regulator.

SST 09268–41045 (09268–52010)

 Torque: 29 N

⋅

m (300 kgf

⋅

cm, 22 ft

⋅

lbf)

(f)  Connect the fuel return hose to the fuel outlet of the

pressure regulator with SST (union), two new gaskets
and union bolt.

SST 09268–41045 (09268–41070)

FI–52

EFI SYSTEM   –   Fuel System (Injectors)

(g)  Install the grommet and a new O–ring to the injector.

(h)  Connect SST (hose) to the injector with SST (union),

and hold the injector and union with SST (clamp).

SST 09268–41045

(i) 

Put the injector into the graduated cylinder.

HINT: Install a suitable vinyl hose onto the injector to prevent
gasoline from splashing out.

(j) 

Using SST, connect terminals +B and FP of the check
(”DIAGNOSIS”) connector.

SST 09843–18020

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

(l) 

Turn the ignition switch ON.

NOTICE: Do not start the engine.

(m)  Connect SST (wire) to the injector and battery for 15

seconds, and measure the injection volume with a
graduated cylinder. Test each injector two or three
times.

SST 09842–30070

Volume: 55–70 cc (3.4–4.3 cu in.) per 15 sec.

Difference between each injector:

10 cc (0.6 cu in.) or less

If the injection volume is not as specified, replace the injector.

2. INSPECT 

LEAKAGE

(a)  In the condition above, disconnect the test probes of

SST (wire) from the battery and check the fuel leakage
from the injector.

SST 09842–30070

Fuel drop: One drop or less per minute

(b)  Disconnect the battery negative (–) cable.
(c) Remove 

SST.

SST 09268–41045 and 09843–18020

(d)  Reconnect the fuel inlet hose to the fuel tube.
SST 09631–22020

Torque: 30 N

⋅

m (310 kgf

⋅

cm, 22 ft

⋅

lbf)

HINT: Use a torque wrench with a fulerum length of 30 cm
(11.81 in.).

FI–53

EFI SYSTEM   –   Fuel System (Injectors)

(e)  Reinstall the fuel pressure regulator to the RH delivery

pipe.

•

Fully loosen the lock nut on the pressure regulator.

•

Apply a light coat of gasoline to a new O–ring, and
install it to the pressure regulator.

•

Completely insert the pressure regulator into the
delivery pipe by hand.

•

Turn the pressure regulator counterclockwise until
the vacuum sensing port faces in the direction
indicated in the illustration.

INSTALLATION OF INJECTORS

(See Components on page 

FI–49

)

1. 

INSTALL INJECTORS AND DELIVERY PIPE
(a)  Install the grommet to each injector.
(b)  Apply a light coat of gasoline to a new O–ring and install

it to each injector.

(c) While  turning  the  injector  clockwise  and

counterclockwise, push it to the delivery pipes. Install
the eight injectors.

(d)  Position the injector connector outward.

(e)  Place the eight insulators and four spacers in position

on the intake manifold.

FI–54

EFI SYSTEM   –   Fuel System (Injectors)

(f) Place 

the 

eight 

injectors 

and 

two 

delivery 

pipes

assembly in position on the intake manifold.

(g) Temporarily install the connector bracket and four

mounting bolts.

(h)  Check that the injectors rotate smoothly.
HINT: If injectors do not rotate smoothly, the probable cause
is incorrect installation of O–rings. Replace the O–rings.
(i) 

Position the injector connector outward.

(j) 

Tighten the four bolts holding the delivery pipes to the
intake manifold.

Torque: 18 N

⋅

m (185 kgf

⋅

cm, 13 ft

⋅

lbf)

2. 

INSTALL FUEL RETURN PIPE
(a)  Temporarily install the return pipe with the bolt, two

gaskets and union bolt.

(b)  Tighten the union bolt holding the return pipe to the

pressure regulator.

Torque: 35 N

⋅

m (360 kgf

⋅

cm, 26 ft

⋅

lbf)

(c) Tighten 

the bolt holding the return pipe to the LH cylinder

head.

3. 

TIGHTEN LOCK NUT ON FUEL PRESSURE REGULATOR

Torque: 29 N

⋅

m (300 kgf

⋅

cm, 22 ft

⋅

lbf)

FI–55

EFI SYSTEM   –   Fuel System (Injectors)