Engine Speed Lowers Extremely Or Engine Stalls - Komatsu PC210-8 Shop Manual

40 Troubleshooting
H-2 Engine speed lowers extremely or engine stalls
Trouble

• Engine speed lowers extremely or engine stalls.

Related
• Carry out all troubleshooting in power mode (P) of working mode.
information
Defective adjustment or
1 malfunction of main relief
valve
Malfunction of PC-EPC
2
valve
Possible
causes and
standard value
Defective adjustment or
3
in normal state
malfunction of PC valve
Defective adjustment or
4
malfunction of LS valve
Clogging of orifice or filter in
5
serve devices
6 Malfunction of servo piston
PC210, 230, 240-8
Cause Standard value in normal state/Remarks on troubleshooting
a
Left work equipment control lever
If oil pressure does not become normal after adjustment, main relief
valve may have malfunction or internal defect. Check main relief
valve directly.
a
a
Pump discharge
PC valve output
If oil pressure does not become normal after adjustment, PC valve
may have malfunction or internal defect. Check PC valve directly.
a
Pump discharge
PC valve output
If oil pressure does not become normal after adjustment, LS valve
may have malfunction or internal defect. Check LS valve directly.
Orifices or filters in pump servo devices may be clogged. Check
them directly.
Servo piston may have malfunction. Check it directly.
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Arm curl relief
Prepare with engine stopped, then run engine at high idle and
low idle and carry out troubleshooting at each speed.
Engine Control lever
Low idle
All levers in neutral
High idle
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Measured oil Measurement
pressure condition
Swing lock switch:
pressure
Arm curl relief
pressure
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Operation of levers and oil pressure ratio
Measured oil
pressure
All levers in neutral
pressure
Almost same
pressure
pressure
UEN00245-02
Main relief pressure
33.3 – 36.8 MPa
2
{340 – 375 kg/cm }
PC-EPC valve
output pressure
2.9 MPa
2
{30 kg/cm }
0.52 – 0.91 MPa
2
{5.3 – 9.3 kg/cm }
Oil pressure ratio
1
ON
Approx. 0.6
(Approx. 3/5)
Travel with no load
(Lever operated half-
way)
1
Approx. 0.6
(Approx. 3/5)
1
9