Testing Fuel Pressure - Komatsu PC88MR-10 Shop Manual

30 Testing and adjusting
Engine and cooling system

Testing fuel pressure

a Testing tools
Sym-
Part No.
bol
799-101-5002 Hydraulic tester
1
790-261-1204 Digital hydraulic tester
G
795-471-1450
2
07005-00812 Seal washer
Place the machine on a level ground and
lower the work equipment to the ground.
Check of the high-pressure circuit
connecting the supply pump, the common
rail, and the injector cannot be performed
due to the extremely high pressure
generated there.
Before testing the fuel system or removing/
installing its parts, wait at least 30 seconds
after stopping the engine until the remaining
pressure in the fuel circuit is released. (Do
not start the work immediately after the
engine is stopped since remaining pressure
is still in the circuit.)
a Measure the fuel pressure in the low-pressure
circuit connecting the priming pump, supply
pump and fuel main filter.
Testing
(PC88MR-AE20-362-K-00-A)
1. Check of pressure in fuel low-pressure circuit
1) Open the engine hood,and remove fuel
pressure pickup plug (1) on 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 }.
30-16
(PC88MR-AE20-360-K-00-A)
Part name
Adapter
(8 x 1.25 mm o R1/8)
3) Start the engine, and measure the pressure
in the fuel low-pressure circuit with the
engine at high idle.
a For standard values, see "Standard value
table for engine".
4) After finishing the test, remove the testing
tools, and restore the machine.
Fuel pressure pickup plug:
7.8 to 9.8 Nm {0.8 to 1.0 kgm}
PC88MR-10