Maintenance
Fault-Finding
119 9831/0650-3 119
Fault-Finding
General
The fault finding procedures are given in the form of flow charts. There are a number of charts, each one
dedicated to a particular fault category.
The charts are designed to identify possible causes by performing checks and where applicable, specific tests
on the engine. Having identified a cause the suggested remedy is given. The charts are designed to identify
causes through a process of elimination, starting with the simplest, most easily rectified faults.
Due to the time and effort involved in removing, dismantling, assembling and replacing an engine, it is
recommended that fault finding procedures are carried out until a fault can be identified with a good degree
of certainty.
There are many reasons why an engine may malfunction, time and effort will be saved by following basic
troubleshooting steps:
• Do not make assumptions.
• If possible, talk to the operator for a description of the fault. Also, check if any recent maintenance or
repair has been completed on the engine.
• Start simple - for instance many starting and running faults can be attributed to low fuel level.
• Systematically work through each of the possible causes.
• Confirm your diagnosis before dismantling and assembling.
• Follow the recommended repair procedures in this manual.
Engine
Table 22. Engine - Will Not Start or Difficult to Start (No Exhaust Smoke)
Cause Remedy
No fuel in supply tank. Check the level in the fuel tank, use sight gauge or
dipstick. Replenish as required.
Starter switch or starter electrical system failure. Check the operation of the starter switch. Check the
correct electrical wires for open or short circuits.
Improper starting procedure. Verify proper starting procedure.
Fuel filter blocked with water or other contamination. Drain fuel/water separator or replace fuel filter.
Defective fuel lift pump (fuel supply inadequate). Check that the lift pump operates and delivers fuel to
the high pressure fuel pump. Check the correct elec-
trical wires for open or short circuits.
Fuel is aerated. Check the fuel system for loose connections and
possible air ingress points. Rectify and bleed the fuel
system.
Check fuel inlet restriction. Maximum inlet restriction to fuel lift pump must not
exceed 100 mm Hg (4 in. Hg).
Air intake or exhaust system blocked. Visually check the air intake and exhaust system for
blockage or obstruction - remove as required. Check
the air filter elements for signs of blocking - replace
as required.
Verify that the fuel return line is not obstructed and
connected to the top of the fuel tank.
Fuel drain return line blocked, not connected proper-
ly.
Do all the necessary fault finding checks before re-
moval of the high pressure fuel pump.
Injectors contaminated. Check the injectors. Use the Servicemaster test pro-
cedure in Servicemaster tools actuator Test. Test and
replace as required.
Table 23. Engine - Will Not Start or Difficult to Start (Exhaust Smoke)
Cause Remedy
Starting procedure incorrect. Verify proper starting procedure.
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