Troubleshooting; Hints On Using The Trouble-Diagnosis Chart - Mitsubishi L3E Service Manual

GENERAL
Service Manual Mitsubishi L-Series diesel engines
Version 08/2004
GENERAL
6

TROUBLESHOOTING

6.1 Hints on using the trouble-
diagnosis chart
1. As for diesel engines, trouble symptoms and
causes are often so complicated that it will be
difficult to locate the root cause by judging from a
trouble symptom.
2. For example, trouble symptoms caused by the
faulty injection pump, faulty injection nozzles and
improper cylinder compression, make the same
kind of phenomenon. When judging the cause of
trouble from examination, be careful to make
conclusion because it can be very complicated.
3. The trouble-diagnosis charts on the following
pages are prepared in such a way of beginning
with the most possible or easiest-to-inspect item
and then proceeding stepwise to less possible or
more complicated items.
4. Before troubleshooting, you should have a right
understanding of the following features about the
structure and fuel combustion in the diesel
engines.
a Normal engine operation is accompanied by
combustion noise (diesel knocking sound).
b A heavy-loaded engine exhausts some black
smoke.
c When operated, an engine may cause
vibration because of high cylinder
compression and large output torque.
d When an engine is accelerated or decelerated
quickly, some hunting may occur.
CAUTION
a. Do not attempt to readjust or disassemble the
injection pump for the purpose of
troubleshooting, without use of a pump tester,
which is indispensable to measure injection
quantity for each cylinder.
b. To check if state of combustion in a cylinder is
normal or not, loosen the injection pipe to cut fuel
feed to that cylinder, and check the slowdown
speed of the engine. Compare the degree of
slowdown with the other cylinders.
ENGLISH
TROUBLESHOOTING
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