Isuzu KB P190. Manual - part 248

6C – 28   FUEL SYSTEM 

 

Injection Nozzle Adjustment 

First nozzle opening pressure adjustment 

1.Clamp the nozzle holder in a vise. 

 

 

 

 

2.  Install the shim, first spring and spring seat in the 

nozzle holder. 

 

 

 

 

3.  Install the collar, second spring, shim, spring seat and 

pushrod in the nozzle holder. 

 

 

 

 

4.  Install the pins, lift piece and spacer in the nozzle 

holder. 

 

 

 

 

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FUEL SYSTEM    6C – 29 

 

5.  Install the pins in the spacer. 

6.  Install the nozzle on the spacer. 

 

 

 

 

 

7.  Hand-tighten the adjustment retaining nut together 

with the gasket to the nozzle holder. 

 

Retaining nut: 

157892-3200 (Bosch AS) 

 

Gasket: 

157892-5100 (Bosch AS) 

(Bosch AS = Bosch Automotive Systems Corporation)

 

 

 

 

8.  Tighten the adjustment retaining nut to the specified 

torque. 

 

Torque: 5.1 kg·m (36.9 Ib·ft/50 N·m) 

 

 

 

 

 

9.  Set the nozzle holder to the nozzle tester. 

10.  Operate the nozzle tester and measure the first nozzle 

opening pressure. 

11.  If the first nozzle opening pressure is not as specified, 

disassemble the nozzle holder and replace the shim 
until the pressure is as specified. 

 

CAUTION: 

• 

Use a micrometer to measure shim thickness. 

 

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6C – 30   FUEL SYSTEM 

• 

First nozzle opening pressure adjusting shims 

Parts No. (ISUZU) 

Thickness (mm) 

115349-0420 0.40 

115349-0430 0.50 

115349-0440 0.52 

115349-0450 0.54 

115349-0460 0.56 

115349-0470 0.58 

115349-0480 0.60 

 

115349-0490 0.70 

 

 

 

 

Full needle valve lift confirmation 

1.  Install the gasket and plug on the adjustment retaining 

nut. 

 

Gasket: 

026508-1140 (Bosch AS) 

8-9422-7602-0 (ISUZU) 

 

Plug: 

157892-1600 (Bosch AS) 

 

 

 

 

 

2.  Position the nozzle holder with the nozzle facing down 

and install the dial gauge holder on the nozzle holder. 

 

Dial gauge holder: 157892-5000 (Bosch AS) 

 

 

 

 

3.  Install the nut on the dial gauge holder. 

 

Nut: 157892-1000 (Bosch AS) 

 

 

 

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FUEL SYSTEM    6C – 31 

 

 
 
 
 

4.  Install the pin to the dial gauge. 

 

 

Note: 

 

The lengths of the pins do not include the 
threaded portions. 

 

Pin (L=100 mm):  157892-5200 (Bosch AS) 

 

Dial gauge: 

157954-3800 (Bosch AS) 

185317-0150 (ISUZU) 

 

 

 

 

5.  Secure the dial gauge to the nozzle holder using the 

nut so that the pin contacts the tip of the first spring 
seat. 

 

CAUTION: 

• 

Secure the dial gauge so that a stroke of 2 mm can 
be measured. 

• 

Do not over-tighten the nut as the dial gauge shaft 
may jam. (Confirm from the dial gauge that the 
shaft moves smoothly.) 

 

 

 

 

6.  Set the nozzle holder to the nozzle tester and put 

needle to zero on the dial gauge. 

7.  Operate the nozzle tester to bleed any air from inside 

the retaining nut and to confirm that no fuel leaks. 

 

 

 

 

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