TM10-3950-672-24-2
Section 2. Troubleshooting Logic
Subject
Page
Engine Diagrams ......................................................................................................................................................... 5-8
Problem Isolation and Correction ................................................................................................................................ 5-8
Troubleshooting Logic (List of Symptoms) ................................................................................................................... 5-9
Troubleshooting Logic
Engine Diagrams
A schematic of each of the major engine systems is provided at the beginning of the Section of the manual devoted to
troubleshooting and repairing that particular system.
The diagrams depict flow through the various engine systems. The information and configuration of the components
illustrated in the drawings are of a general nature. Some items for specific applications and installations may be
different.
Each Section also contains a discussion regarding diagnosing malfunctions for that specific system.
A knowledge of the systems can help you troubleshoot and repair the engine.
Problem Isolation and Correction
The following Troubleshooting Logic is designed to help you organize your study of a problem and to plan a procedure to
correct it. The series of fault/logic charts given do not provide all the answers, but they should stimulate a train of
thought that will lead you to the source of the trouble.
Be sure to consider any maintenance or repair action that could have caused the problem.
If the engine surges or runs rough initially after not being used for 2 months or more, do not assume that the engine has
a malfunction. Varnish can form on the internal parts of the injection pump and the oil film can drain from the piston
rings. Operate the engine for at least 5 minutes before troubleshooting.
The basic procedure is as follows:
Study the problem thoroughly.
Relate the symptoms to your knowledge of the engine components and systems.
Double-check before beginning the disassembly.
Solve the problem by deduction starting with the easiest things.
Determine the cause of the problem and make a thorough repair.
After making corrections, operate the engine in normal conditions to verify the cause of the problem was
corrected.
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