PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IO-G-T-00-001e B
February 2016
GAS ENGINES TROUBLESHOOTING
6/10
SYMPTOM
PROBABLE CAUSE
REMEDY
Engine shows signs of ignition
failures
Too lean air-fuel mixture
Readjust carburettor mixture valve.Check
NOx sensor or lambda sensor signal
(1)
Spark plug failure
Check, regap or change spark plus as
appropriate
Coil or high-voltage wire failure
Change wires or coils that are out of
specifications
Ignition module failure
Change module
Knocking
Whenever knocking occurs,
endoscopic examination is
necessary to determine the
extent of the fault and to be
able to change any affected
parts.
If the engine incorporates a
Detonation Detection System,
check the sensors to see if
they fail to detect knocking on
time.
High temperature of intake air
Clean air cooler, check thermostats and
auxiliary circuit pump
Oil jet broken or bent
Change jet. Inspect piston dome for signs of
overheating and, if any, change piston
Intake or exhaust valve drop
Change cylinder head and, where
appropriate, sleeve, piston...
Excessively advanced ignition
Check ignition timing
High water temperature in main circuit
1. Not enough coolant
2. Air in the main circuit
3. Water
leak
4. Dirty radiator or heat exchanger
5. Fan
failed
6. Damaged
pump
7. Damaged cylinder head gaskets
1. Add coolant into the circuit
2. Vent the circuit
3. Repair
leak
4. Clean radiator or heat exchanger
5. Change
fan
6. Repair or change pump
7. Change cylinder head gasket
Overload due to wrong reading of power
signal
Calibrate power signal
Too rich air-fuel mixture
Readjust carburettor mixture valve.
Check MAP and MAT sensors signal
(2)
Check NOx sensor or lambda sensor signal
(1)
Broken or damaged spark plug
Change spark plug
Overhead valves do not close correctly
Change or rework cylinder head
Foreign bodies in the combustion chamber
Remove foreign bodies
Carburetion control failure
Check control program
Failure of gas flow regulating valve
Change gas flow regulating valve
Sudden change in gas quality
Check against chromatogram if available.
Readjust carburettor mixture valve
(3)
Check programming if electronic system
installed
(2)
Seizure
Change any parts concerned.
(1)
Engines with NOx sensor or lambda sensor carburetion
(2)
Engines with electronic carburetion
(3)
Engines with Mechanical carburetion
6.1.6
O&M_2.002211.810_A_10_2016