Komatsu 170-3 Series, Руководство по ремонту, Страница: 134 / 454

12-8
170-3 SERIES
TESTING AND ADJUSTING
TROUBLESHOOTING FOR
INJECTOR
★
If the torque converter stall speed or the hydrau-
lic pump relief speed is low and bad combustion
seems to be caused by defective fuel injection,
perform troubleshooting for the injector accord-
ing to the following procedure.
1. Stop the engine and wait for it to cool down.
★
A guideline for judging if the engine has
cooled down is that the temperature of the
exhaust manifold is less than 20°C above the
ambient temperature.
2. Make measurement marks a to the exhaust
manifold outlets of the all cylinders.
★
Make the marks at the same points of the
tops or bottoms of the exhaust manifolds of
the all cylinders.
3. Using heat gun D , measure the temperature at
the exhaust manifold outlet port of each cylinder
before starting the engine.
★
Apply the measurement light (center) of the
heat gun to mark
a of each cylinder to pre-
vent dispersion of the measurement results
caused by difference of the measuring
points.
4. Run the engine at low idling speed.
5. Using heat gun D , measure the temperature at
the exhaust manifold outlet port of each cylinder
3 minutes, 6 minutes, 9 minutes, and 12 minutes
after starting the engine.
★
Apply the measurement light (center) of the
heat gun to mark
a of each cylinder to pre-
vent dispersion of the measurement results
caused by difference of the measuring
points.
6. Compensate the measured value for each cylin-
der 12 minutes after starting the engine and
judge if there is any cylinder with a problem.
★
Compensation value
Unit:°C
★
Method of judgement
After compensating, add up the values for
the exhaust gas temperature and calculate
the average value. Any cylinder that is more
than 20ºC lower than the average value can
be considered abnormal.
★
Measurement and judgement example 1
No. 2 cylinder is more than 20°C lower than
the average value, so judge it as abnormal.
Unit:°C
★
Measurement and judgement example 2
No. 3 cylinder is more than 20°C lower than
the average value, so judge it as abnormal.
Unit:°C
★
Measurement and judgement example 3
No cylinder is more than 20°C lower than the
average value, so judge all cylinders as nor-
mal.
Unit:°C
Cylinder No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
Compensation
value
+20 +5 0 0 +5 +20
Cylinder No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
Measured value 85 62 79 112 89 82
Compensated
value
105 67 79 112 94 102
Average value 93
Cylinder No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
Measured value 86 96 73 91 94 103
Compensated
value
106 101 73 91 99 123
Average value 99
Cylinder No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
Measured value 70 88 88 93 86 72
Compensated
value
90 93 88 93 91 92
Average value 91
TROUBLESHOOTING FOR INJECTOR
➄
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