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(3) Inspection and adjustment: Injection Pressure and Spray Pattern of Fuel Injection Valve
Wear protective glasses when testing injection from the fuel injection valve. Never approach the injection
nozzle portion with a hand. The oil jetting out from the nozzle is at a high pressure to cause loss of sight
or injury if coming into careless contact with it.
(a) Injection pressure measurement
Model
Standard
Mpa(kgf/cm
2
)
3IRH2N 3IRH8N (CL )
19.6-20.6
(200-210)
3IRH2N 3IRH8N (VM )
4IRI8T
21.6-22.6
(220-230)
[NOTICE]
As for the opening pressure of the brand-new fuel
nozzle, about 0.5Mpa(5kgf/cm) declines by the engine
operation for about 5 hours because of the initial wear-
out of a spring etc. Therefore, adjust 0.5MPa(5kgf/cm)
higher than the standard value of the above table when
adjusting a new fuel nozzle of a spare part.
Remove carbon deposit at the nozzle hole thoroughly
before measurement.
1) Connect the fuel injection valve to the high-
pressure pipe of the nozzle tester.
2) Operate the nozzle tester lever slowly and read the
pressure at the moment when the fuel injection from
the nozzle starts.
3) If the measured injection pressure is lower than the
standard level, replace the pressure adjusting shim
with a thicker one.
Thickness of pressure adjusting shims
mm
Injection pressure adjustment
0.13, 0.15, 0.18, 0.4, 0.5, 0.8
The injection pressure is increased by approx. l.9 MPa(l9 kgf/cm
2
),
when the adjusting shim thickness is increased by 0.l mm.
