Komatsu 75001, Shop Manual

Page: 407 / 1293

SEN03836-01
30-110
24
WA250, 250PZ-6
110 Testing and adjusting, Part 1
Measuring fuel pressure
Measuring fuel pressure
1
a Necessary tools
k Put chocks under the tires securely.
k When measuring, check that there are no
persons around the machine.
a Test only the fuel pressure in the low-pressure
circuit from the feed pump through the fuel
main filter to the supply pump and in the return
circuit between the supply pump/common rail/
injector and fuel tank.
k Since the pressure in the high-pressure cir-
cuit from the supply pump through the
common rail to the fuel injector is very
high, it cannot be measured.
1. Measuring pressure in fuel low-pressure
circuit
1)
Remove fuel pressure pickup plug (1)
from the fuel main filter.
2) Install adapter G2 and nipple [1] of
hydraulic tester G1 and connect them to
oil pressure gauge [2].
a Use the oil pressure gauge of 2.5
MPa {25 kg/cm
2
}.
3) Run the engine at low idle and measure the
pressure in the fuel low-pressure circuit.
a If the pressure in the fuel low-pres-
sure circuit is in the following range, it
is normal.
k
If the engine cannot be started, you
may measure the fuel pressure
while rotating the engine with the
starting motor. Do not rotate for
more than 20 seconds continu-
ously, however, for protection of
the starting motor.
4) After finishing measurement, remove the
measuring tools and return the removed
parts.
3 Fuel pressure pickup plug:
10 ± 2 Nm {1 ± 0.2 kgm}
Symbol Part No. Part name
G
1
799-101-5002 Hydraulic tester
790-261-1204 Digital hydraulic tester
2
6732-81-3170
Adapter
(10 × 1.0 mm
o PT1/8)
6215-81-9710 O-ring
3 799-401-2320 Hydraulic tester
4 795-790-5110 Screw
5 799-201-2202 Boost gauge kit
During cranking
0.3 – 1.1 MPa
{3.1 – 11.3 kg/cm
2
}
At low idle
0.5 – 1.3 MPa
{5.1 – 13.3 kg/cm
2
}