1-111-11THDC / THDCP - 954 / 955 / 974 (Rev. 06/03)THDC / THDCP - 954 / 955 / 974 (Rev. 06/03)
Engine TroubleshootingEngine Troubleshooting(Cummins QSM11-C330)(Cummins QSM11-C330)
(Illus(Illustration tration 1-6)1-6)
The following chart includes some of the problemsThe following chart includes some of the problems
that an operator may encounter during the servicethat an operator may encounter during the service
life of a Cummlife of a Cummins diesel engiins diesel engine. ne. Always cAlways checkheck
the easiest and obvious things first, such as thethe easiest and obvious things first, such as the
master disconnect switch, the neutral start switch,master disconnect switch, the neutral start switch,
an empty fuel tank, closed fuel shut off, dead bat-an empty fuel tank, closed fuel shut off, dead bat-
tery or corrtery or corroded terminaloded terminals. s. Study the problemStudy the problem
thoroughly before starting to work on the engine.thoroughly before starting to work on the engine.
Ask Ask yourself yourself the the following following questions.questions.
1. 1. What wWhat were the waere the warninrning signs prg signs precedeceding theing the
trouble?trouble?
2. 2. Has tHas the enginhe engine been sube been subjecjected to reted to recentcent
repair or maintenance?repair or maintenance?
3. 3. Has a siHas a similmilar troar trouble ocuble occurcurred befored before?re?
4. 4. If the engiIf the engine stine still runll runs, is is, is it safe to cont safe to contintinueue
operation of the engine in an effort to diag-operation of the engine in an effort to diag-
nose the trouble?nose the trouble?
Check the items most easily and inexpensivelyCheck the items most easily and inexpensively
corrected before proceeding to the more difficult,corrected before proceeding to the more difficult,
time consumtime consuming and expensiving and expensive items. e items. After aAfter a
malfunction has been corrected, locate and cor-malfunction has been corrected, locate and cor-
rect the cause of the trouble to prevent recurrencerect the cause of the trouble to prevent recurrence
of the same trouble.of the same trouble.
PPrroobblleem m CCaauusse e CCoorrrreeccttiioonn
1. 1. Air Air comcomprespressor sor airair
pressure risespressure rises
slowlyslowly
1. 1. Intake aiIntake air rer restricstriction to tion to air cair compres-ompres-
sor is sor is excessexcessive.ive.
2. 2. Air Air syssystem tem leakleaks.s.
3. 3. CarCarbon builbon buildup excdup excessiessive in the aive in the airr
discharge line.discharge line.
1. 1. RemRemove ove resrestritrictiction.on.
2. 2. ChecCheck for aik for air compr compresressor gassor gasket,ket,
hoses, and fihoses, and fitting leaktting leaks. s. Check forCheck for
safety psafety pressure vressure valve leaksalve leaks. . Rat-Rat-
ing must be 135 psi.ing must be 135 psi.
3. 3. ChecCheck valk valve or cve or cyliylinder hnder head foread for
carbon buildup and remove.carbon buildup and remove.
4. 4. ContContact a Cact a Cummummins Ains Authoruthorizedized
Repair Facility.Repair Facility.
2. 2. Air Air comcomprespressorsor
cycles frequentlycycles frequently
1. 1. Air Air syssystem tem leakleaks.s.
2. 2. CarCarbon builbon buildup is exdup is excescessivsive in thee in the
air discharge line, check valve, orair discharge line, check valve, or
cylinder head.cylinder head.
3. 3. Air cAir comprompressessor pumor pumping tiping time isme is
excessive.excessive.
1. 1. BlocBlock thk the tre truck’uck’s ws wheelsheels. . InsInspectpect
the air system for leaks with thethe air system for leaks with the
parking brakes applied and re-parking brakes applied and re-
leased. leased. Check for Check for leaks frleaks from theom the
air compressor gaskets and the airair compressor gaskets and the air
system hoses, fittings, and valves.system hoses, fittings, and valves.
2. 2. ChecCheck for air dk for air discischarge lharge line, chine, checkeck
valve, and cylinder head for carbonvalve, and cylinder head for carbon
buildup. buildup. Replace tReplace the air che air compres-ompres-
sor discharge line if required.sor discharge line if required.
3. 3. ReplReplace the desace the desicciccant carant cartritridge indge in
the air drythe air dryer (if equier (if equipped). pped). CheckCheck
the air compressor duty cycle.the air compressor duty cycle.
4. 4. ContContact a Cact a Cummummins Ains Authoruthorizedized
Repair Facility.Repair Facility.
3. 3. Air Air comcomprespressorsor
noise is noise is excessexcessiveive
continuedcontinued
1. 1. CarCarbon builbon buildup excdup excessiessive in the aive in the airr
discharge line.discharge line.
1. 1. RefRefer to Coer to Correrrectiction 3. of Pron 3. of Probleoblemm
1. of this troubleshooting chart.1. of this troubleshooting chart.
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