Komatsu ecot3 PC300LC-8 Shop Manual page 363

30 Testing and adjusting
3) Run the engine at high idle and measure
drop of the pressure of the fuel low-pressure
circuit.
Pressure drop in the fuel low-pressure cir-
q
cuit =
Fuel filter inlet pressure - Fuel pressure
outlet pressure
a If the pressure drop in the fuel low-pres-
sure circuit is in the following range, it is
normal.
Standard pressure drop values for the
q
fuel low-pressure circuit:
Max. 0.14 MPa {Max. 1.4 kg/cm
a When the measured pressure drop ex-
ceeded the standard value, clogging of
the fuel filter should be suspected.
4) After finishing measurement, remove the
measuring tools and return the removed
parts.
q Fuel pressure pickup plug:
6. Testing fuel lift pump outlet pressure (supply
pump section)
1) Remove fuel pressure pickup plug (2) of the
supply pump.
PC300, 350-8
20 - 22 Nm {2.0 - 2.2 kgm}
2) Connect M10 computer check fitting G4to
gauge G3.
2
}
3) Turn the starting switch ON, operate fuel lift
pump (5), and measure the fuel lift pump
outlet pressure.
Reference: Fuel lift pump (5) is installed to
cooling plate (7) on the back side of engine
controller (6).
a The fuel lift pump operates for 30 sec-
onds after the starting switch is turned ON
and then stops. Measure the pressure
while the pump is operating.
a If the fuel lift pump outlet pressure is in the
following standard range, it is normal.
q Standard fuel lift pump outlet pressure
(supply pump section):
a If the fuel lift pump outlet pressure is not
in the standard range, perform the follow-
ing checks.
q Check that fuel is in the fuel lift pump.
q If fuel is not in the fuel lift pump just af-
ter the fuel filter is replaced or a fuel
system part is removed and returned,
operate the fuel lift pump 3 - 4 times
with the starting switch to bleed air
from the fuel circuit and fill the pump
with fuel and then measure the outlet
pressure again.
SEN02625-06
Min. 34 kPa {0.35 kg/cm
2
}
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