Isuzu engine 4j series. Service manual - part 70

6C - 24  ENGINE FUEL

Nozzle Lapping Procedure

1. Lap the nozzle needle 

!

 and the nozzle body 

"

 by

applying a compound of oxidized chrome and animal
oil 

#

.

NOTE:

Do not apply an excessive amount of the oxidized
chrome and animal oil compound to the injection
needle valve seat area.  Applying too much compound
will cause the injection nozzle needle and the injection
nozzle body cavity to wear excessively.
2. Carefully wash the needle valve and the nozzle body in

clean diesel fuel after lapping.

Nozzle Body and Needle Valve Inspection

Check the nozzle body and the needle valve for damage
and deformation.
The nozzle and body assembly must be replaced if either
of these two conditions are discovered during inspection.

Reassembly

7. Nozzle 

Holder

6. Adjusting 

Shim

5. Spring

4. Spring 

Seat

3. Spacer

2. Injection Nozzle

1. Retaining Nut

Tighten the retaining nut to the specified torque.

N∙m (Kg∙m/lb∙ft)

                                                                                                                   

34 (3.5/25)

                                                                                                                   

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ENGINE FUEL  6C - 25

Injection Nozzle Adjustment

1) Attach the injection nozzle holder to the injection

nozzle tester.

2) Apply pressure to the nozzle tester to check that the

injection nozzle opens at the specified pressure.

kPa (kg/cm

2

/psi)

                                                                                                                   

18,142 (185/2630)

                                                                                                                   

If the injection nozzle does not open at the specified
pressure, install or remove the appropriate number of
adjusting shims to adjust it.

Adjusting Shim Availability

mm (in)

Range

0.50 - 1.50 (0.02 - 0.06)

Increment

0.025 (0.001)

Total No. of Shims

40

Removing or installing one shim will increase of decrease
the nozzle opening pressure approximately 369.46 kPa
(3.77 kg/cm

2

/53.6 psi).

WARNING:

TEST FLUID FROM THE INJECTION NOZZLE WILL SPRAY
OUT UNDER GREAT PRESSURE.  IT CAN EASILY
PUNCTURE A PRESON'S SKIN.  KEEP YOUR HANDS
AWAY FROM THE INJECTION NOZZLE TESTER AT ALL
THE TIMES.

INSTALLATION (4JB1/4JB1T Engine)

3. Injection Nozzle

1) Install the injection nozzle gasket 

!

 and the O-ring 

"

to the injection nozzle holder 

#

.

Be sure that the O-ring fits snugly in the injection
nozzle groove.

2) Apply engine oil to the cylinder head nozzle holder

hole.

3) Install the nozzle holder together with the nozzle holder

bracket 

$

 to the cylinder head.

N∙m (Kg∙m/lb∙ft)

                                                                                                                   

37 (3.8/27)

                                                                                                                   

2. Leak Off Hose

1. Injection Pipe

6C-24-1.tif

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6C-24-3.tif

6C - 26  ENGINE FUEL

INJECTION PUMP ASM (4JB1/4JB1T, 4JG2 Gear Drive Type)

REMOVAL

Preparation:

•

Disconnect battery ground cable.

•

Drain coolant.

1. Cooling Fan Assembly

•

Remove clamp nut, and remove cooling fan assembly,
distant pipe, and fan pulley.

2. Fan Shroud

3. Power Steering Pump Drive Belt (P/S Model)

•

Loosen Power Steering pump mounting bolt and
adjust bolt, and remove the drive belt.

4. A/C Compressor Drive Belt (A/C Model)

•

Loosen A/C compressor idler pulley lock nut, adjust
bolt and remove the drive belt.

6C-25-1.tif

ENGINE FUEL  6C - 27

5. AC Generator Drive Belt

•

Loosen AC generator mounting bolt (under side) and
adjust plate lock bolt, and remove the drive belt.

6. Noise Shield Cover

7. Noise Cover Spacer

8. Air Intake Duct

9. Injection Pump Control Cable

•

Removal the control cable bracket bolt and remove the
control lever side.

10. Fuel Hose

•

Disconnect the fuel feed hose and fuel return hose.

11. CSD (Cold Starting Device) Water Hose

•

Disconnect the water hose from injection pump side.

12. Injection Pump Harness

•

Remove the tachometer sensor (with tachometer)
CSD solenoid, fuel cut solenoid.

13. Injection Pipe

•

Release pipe clip.

•

Remove the flare nut on the pump side.

•

Remove the flare nut on the injection nozzle side, and
remove the injection pipe.

CAUTION

•

Be sure to plug the injection nozzle holder and delivery
holder to prevent the entry of foreign matter.

14. Injection Pump Assembly

•

Remove pump mounting nut

•

Loosen injection pump rear bracket adjuster lock bolt.

•

Remove the mounting bolt on the engine side, and pull
out the pump from the engine.

NOTE:

Plug the injection pump delivery holder parts with the
shipping caps (or the equivalent) to prevent the entry
of foreign materials.

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