Isuzu N-Series. Manual - part 394

6C-54 FUEL SYSTEM

Injection Volume Adjustment (4HF1-2 Engine)

Test Conditions

4HF1-2 (Bosch distributor type)

Identification Plate and Number

Use the data following the injection pump identification
number to adjust the injection volume.

Item

Condition

Injection nozzle and holder assembly

Bosch AS Part No.: 105118-4680

Injection nozzle

Bosch AS Part No.: 105017-2200

Nozzle holder

Bosch AS Part No.: 105048-3673

Injection nozzle opening pressure

kPa (kg/cm

2

 / psi)

13,042 (133 / 1,891)

Injection line dimensions

Inside diameter

mm (in)

2.0 (0.079)

Outside diameter

mm (in)

6.0 (0.236)

Length

mm (in)

450 (17.7)

Fuel delivery pressure

kPa (kg/cm

2

 / psi)

19.6 (0.2 / 2.84)

Test fuel

SAE Standard Test Diesel Fuel (SAE J967d)

ISO Standard Test Diesel Fuel (ISO 4113)

Test fuel temperature

°C (°F)

40 — 45 (104 — 113)

Identification numbers

101742-1630

Legend

A. Isuzu part No. (Pump assembly No.)
B. Bosch pump assembly No.

N6A0946E

FUEL SYSTEM 6C-55

Injection Volume and Governor Performance Diagram

Injection volume

Timing Advance Specification

Governor Adjustment (4HF1-2)

Identification Numbers

: 104742-1630

[4HF1-2 Engine]

Pre-stroke

: No. 1 plunger 0.45

±0.05 mm (0.0177±0.0020 in)

Injection order

: 1 — 3 — 4 — 2 (interval 90

°±30′) Plungers are numbered from the Governor side

Pump speed (rpm)

Injection volume 

(mm

3

/strokes)

Uneven amplitude 

(mm

3

/strokes)

Oil temperature

(

°C (°F))

Remarks

500

48.2 

± 4.5

—

48

±2 (118±36)

960

60.3

±1.0

5.0

50

±2 (122±36)

Basic

1280

63.9

±3.5

—

50

±2 (122±36)

1600

61.4

±4.5

—

50

±2 (122±36)

1925

17.9

±3.0

5.5

50

±2 (122±36)

Basic

300

10.1

±2.0

2.0

48

±2 (118±36)

Basic

150

37.0

±10

—

48

±2 (118±36)

Pump Speed (r.p.m.)

1,100

1,280

1,600

1,800

Degree for Angle of Lead (deg.)

0.7

2.8

6.2

Finish 6.5

N6A1656E

6C-56 FUEL SYSTEM

Injection Volume Adjustment (4HG1 Engine)

Test Conditions

4HG1 Engine

Identification Plate and Number

Use the data following the injection pump identification
number to adjust the injection volume.

Item

Condition

Injection nozzle and holder assembly

Bosch AS Part No.: 105118-6041

Injection nozzle

Bosch AS Part No.: 105017-1850

Nozzle holder

Bosch AS Part No.: 105048-3673

Injection nozzle opening pressure

kPa (kg/cm

2

 / psi)

18,142 (185 / 2,631)

Injection line dimensions

Inside diameter

mm (in)

2.0 (0.079)

Outside diameter

mm (in)

6.0 (0.236)

Length

mm (in)

600 (23.6)

Fuel delivery pressure

kPa (kg/cm

2

 / psi)

156.9 (1.6 / 22.75)

Test fuel

SAE Standard Test Diesel Fuel (SAE J967d)

ISO Standard Test Diesel Fuel (ISO 4113)

Test fuel temperature

°C (°F)

40 — 45 (104 — 113)

Identification numbers

101401-7430
101401-7440

Legend

A. Isuzu part No. (Pump assembly No.)
B. Bosch pump assembly No.

N6A0946E

FUEL SYSTEM 6C-57

Injection Volume and Governor Performance Diagram

Injection Volume

Timing Advance Specification

Identification Numbers

: 101401-7430/101401-7440

[4HG1 Engine]

Pre-stroke

: No. 1 plunger 4.1

±0.05 mm (0.1614±0.0020 in)

Injection order

: 1 — 3 — 4 — 2 (interval 90

°±30′) Plungers are numbered from the Governor side

Tappet clearance

: Bolt adjustment type

: More than 0.3 mm (0.0118 in) for all cylinders.

: Shim adjustment type

: Manually rotate the camshaft 2 — 3 times and confirm that it 
rotates smoothly.

Adjusting point

Pump speed (r.p.m.)

Injection volume (cc/

1000 strokes)

Variance (%)

Remarks

1,310

70.5

±1.6

±4

Basic

H

315

10

±1.3

±10.0

A

1,310

70.5

±1

—

Basic

B

1,600

(75.5)

±2

—

C

520

(64)

±2

—

D

960

(70.5)

+2

−0

—

I

150

(95)

+16

−0

—

Pump Speed (r.p.m.)

1,050 or less

1,000

1,600 or more

Degree for Angle of Lead (deg.)

Start

0.5 or less

Finish 5

±0.5