All Of Work Equipments, Swing And Travel Operations Lack Speed Or Power - Komatsu PC88MR-10 Shop Manual

H-1 All of work equipments, swing and travel operations lack speed or
power
(PC88MR-A8A-400-A-Z0-A)
All of work equipment, swing and travel operation lacks speed or power.
Failure
Perform all troubleshooting with working mode set in power (P) mode.
If any failure code is displayed, perform troubleshooting for that failure code first.
Related
(DXA8KA or DXA8KB)
information
Pump pressure can be checked with monitoring function. (monitoring code: 01100)
No. Cause
Malfunction of unload
1
valve
Defective adjustment of
2
main relief valve
Malfunction of main
3
relief valve
Malfunction of self-
4
pressure reducing valve
Malfunction of PC-EPC
5
valve
Defective adjustment of
6
PC valve
PC88MR-10
Troubleshooting of hydraulic and mechanical system (H-
Procedure, measuring location, criteria, and remarks
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Unload pressure
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Main relief pressure
When pressure cannot be adjusted to normal level, check main relief valve for
malfunction (fatigue of spring) and internal defect (defective valve seat).
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Control circuit
source pressure
a Since relief valve of self-pressure reducing valve is not adjustable, replace
self-pressure reducing valve assembly if normal pressure is not obtained.
a Be ready with engine stopped, then perform troubleshooting with engine
running at low idle and at high idle.
Engine at low idle and all levers in
PC-EPC valve
output pressure
Engine at high idle and all levers
Replace PC-EPC valve if any failure is found.
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Oil pressure to be
measured
Pump discharge
pressure
PC valve output
pressure
When pressure cannot be adjusted to normal level, check PC valve for
malfunction (fatigue of spring) or internal defect (stuck or seized PC spool).
All levers in NEUTRAL
Arm IN hydraulic relief
All levers in NEUTRAL
NEUTRAL
in NEUTRAL
Measurement condition
Arm IN hydraulic relief
Arm IN hydraulic relief
40 Troubleshooting
mode)
3.4 ± 1.0 MPa
{35 ± 10 kg/cm 2 }
26.5 ± 1.5 MPa
{270 ± 15kg/cm 2 }
3.2 ± 0.5 MPa
{33 ± 5 kg/cm 2 }
1.72 to 0.5 MPa
{17.5 to 26.5 kg/cm 2 }
0.69 to 1.42 MPa
{7.0 to14.5 kg/cm 2 }
Oil pressure ratio
1
Approx. 0.2 to 0.6
40-465