SYMPTOMS OF MALFUNCTIONS
WHICH MAY AFFECT
ENGINE EMISSIONS
Certain symptoms of malfunctions are evident to the operator which can indicate the need for service to provide proper
emission control. The following information describes some of the common indications of trouble and the usual causes.
Operators should be alert to these symptoms and have corrections made promptly.
SYMPTOM
USUAL CAUSES OF PROBLEM
Excessive white smoke.
Indicates unburned fuel in exhaust due
to the following:
1. Misfiring due to engine not being up to
compression.
2. Misfiring due to faulty injector or low
compression.
Excessive blue smoke
Indicates lubricating oil in the exhaust
due to the following:
1. "Pull-over" from the oil bath air
cleaner.
2. Leaking blower or turbocharger seals.
3. Improperly sealing oil control rings.
4. Worn valves, valve guides, stems or seals.
Excessive black smoke
Indicates incomplete burning of the fuel
due to the following:
1. Overfueling due to increased fuel in-
jection from enlarged injector tip
orifices.
2. Poor atomization of fuel due to
deposits around injector tip.
3. Inadequate air supply due to clogged
air cleaners, dirty blower screen, turbo-
charger failure or increased exhaust
back pressure.
4. Overfueling due to engine operation at
speeds below 60% of rated speed.
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