Speed Or Power Of Whole Work Equipment, Swing, And Travel Is Low - Komatsu PC200-8M0 Shop Manual

500 Troubleshooting of hydraulic and mechanical system (H-mode)
H-1 Speed or power of whole work equipment, swing, and travel is low
H-1 Speed or power of whole work equipment, swing, and travel is low
q
Failure Speed or power of all work equipment, swing, and travel is low.
Related infor-
q
Perform all troubleshooting with working mode in power mode (P).
mation
1 Malfunction of unload valve
Defective adjustment or mal-
2
function of main relief valve
Malfunction of self-pressure
3
reducing valve
Probable
causes and cri-
teria
Malfunction of PC-EPC
4
valve
Defective adjustment or mal-
5
function of PC valve
6 Malfunction of LS-EPC valve
PC200, 200LC, 220, 220LC-8M0
Cause
a Be ready with engine stopped, then troubleshoot with engine
high idle.
All levers in the neutral position
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Left work equipment control
If normal oil pressure is not obtained by adjustment, main relief
valve may malfunction or have internal defect. Check main relief
valve.
a Be ready with engine stopped, then troubleshoot with engine
high idle.
All levers in the neutral position
a Be ready with engine stopped, then troubleshoot with engine at
low speed and engine high idle.
a Be ready with engine stopped, then troubleshoot with engine at
full speed.
Measured oil pres-
Pump discharge
PC valve output pres-
If normal oil pressure is not obtained after adjustment, PC valve
may malfunction or have internal defect. Check PC valve.
a Be ready with engine stopped, then troubleshoot with engine at
full speed.
Travel speed
Criteria and troubleshooting procedure
Control lever
lever
Arm IN relief
Control lever
Engine Control lever
Low idle
All levers in the neu-
tral position
High idle
Measurement condi-
sure tions
Swing lock
pressure
Arm IN relief
sure
Travel lever
Lo Neutral
Hi Operation
SEN06139-00
Unload pressure
3.5 ± 1.0 MPa
2
{36 ± 10 kg/cm
Main relief pressure
33.3 to 37.2 MPa
{340 to 380 kg/cm
Control circuit source pressure
2.84 to 3.43 MPa
2
{29 to 35 kg/cm
PC-EPC valve out-
put pressure
Approx. 2.9 MPa
{Approx. 30 kg/cm
0.52 to 0.91 MPa
{5.3 to 9.3 kg/cm
Ratio of oil pressures
1
Switch: ON
Approx. 0.6 (Approx.
3/5)
LS-EPC valve
output pressure
Approx. 2.9 MPa
{30 kg/cm
0 MPa
{0 kg/cm
40-500
}
2
}
}
2
}
2
}
2
}
2
}
9