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TM 10-3930-671-24
4.2. Engine Troubleshooting
Troubleshooting Guide .................................................................. F-68
When diagnosing and correcting the cause of trouble
with a diesel engine, do not begin by disassembling
components. Instead, start by analyzing the complaint or
symptoms. Then, systematically determine the probable
cause. Make a preliminary investigation of the trouble as
follows:
1.
Check with the operator or his supervisor before
you start troubleshooting. Ask the operator the
following:
a.
Did you hear any unusual noise?
b.
Is the trouble accompanied by any other
faulty conditions?
c.
When did trouble occur?
d.
How did the trouble happen? Did the trouble
happen suddenly? Any abnormality before
the trouble happened?
e.
Had the engine recently been repaired when
the trouble occurred? When?
f.
Has the same trouble occurred before?
2.
If it is necessary to operate a faulty engine for
the purpose of troubleshooting, be sure to ask
for the user’s consent about possible progress of
the trouble which could result from the operation.
3.
Be sure the problem exists. If it is difficult to
judge whether a faulty condition is to be
regarded
as
a
trouble
or
not,
use
the
troubleshooting chart as a guide.
4.
It is possible to avoid unnecessary disassembly
work by diagnosing the cause of the trouble
accurately on the basis of the questions asked of
the
user
and
the
information
in
the
troubleshooting chart. Take the time necessary
for sufficient preliminary investigation. Hasty
disassembly work can also make it difficult to
reproduce
the
troubled
condition
and,
sometimes, leads to disappearance of the
evidence of the cause of the trouble.
5.
Start with the easiest and least time-consuming
solution. When several items are suspected to
be the cause of the trouble, examine them,
starting with the easiest one.
6.
Try to think of the reason why the trouble
happened. Do not confine your effort to the
correction of the present trouble, but try to detect
the fundamental cause, if any, of the trouble and
correcting or adjusting it.
7.
A good rule to follow in locating trouble is to
never make more than one adjustment at a time.
Locate the trouble by a process of elimination.
The cause is usually simple, rather than
mysterious and complicated.
The following troubleshooting guide lists most of the
usual complaints or troubles encountered in routine
operation of all diesel engines, with probable cause and
troubleshooting procedure.
F-67
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