Troubleshooting; Before Troubleshooting - Mitsubishi L Series Service Manual

TROUBLESHOOTING

1. Troubleshooting

1.1 Before troubleshooting

(a) For the fuel injection pump, the injection quantity
of each cylinder can be measured only with a
pump tester. Do not adjust or disassemble the fuel
injection pump even during troubleshooting unless
absolutely necessary.
(b) To inspect the combustion state of each cylinder,
loosen the fuel injection pipe of any cylinder to
stop injection, and compare the extent of a drop in
the engine speed with that of other cylinders
(1) Troubles of the diesel engine often occur in
combination of various problem causes, and therefore it
is often very difficult to determine the defect from a
problem phenomenon.
Especially a similar phenomenon occurs in troubles of
the fuel injection pump, fuel injection nozzles and
compression pressure. It is, therefore, necessary to
conduct a careful study to determine the cause.
From the reason above, troubleshooting described in
this section is summarized as the inspecting order from
items which are more likely to cause problems or items
easy to inspect in sequence.
(2) The diesel engine has the following characteristics from
its structure and combustion system. It is necessary to
fully understand these characteristics before performing
troubleshooting.
･ The engine produces unique combustion noise (diesel
knock) in the normal condition.
･ The engine discharges slight black smoke at heavy
load.
･ High compression and high torque cause vibration on
a single unit of the engine.
･ Slight hunting is caused during acceleration and
deceleration.
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