Perkins NJ Series Troubleshooting Manual page 70

70
Troubleshooting Section
2. When the ambient temperature exceeds the
capability of the cooling system or the air charge
cooler, operate the engine at a reduced load or
operate the engine at a reduced speed.
3. When possible, modify the cooling system and
the air charge cooler in order to make the system
suitable for local conditions.
Intake Air Restriction and/or High Altitude
Low air pressure at the air intake for the turbocharger
can be caused by a restriction in the air intake or a
high altitude. When the pressure of the intake air
is low, the turbocharger (if equipped) works harder
in order to achieve the desired intake manifold
pressure. This increases intake air temperature.
Measure the intake manifold pressure while the
engine is operating under load. For specific data,
refer to the Perkins Technical Marketing Information
for the engine.
Intake Air Restriction
1. Check for blocked air filters. Check for obstructions
in the air intake.
2. Replace the air filters or remove the obstruction
from the air intake.
High Altitude
Make sure that the settings for the engine are correct
for the altitude.
Intake Air from a Heated Area
1. Ensure that the air inlet system is not receiving
air from a heated area.
2. If necessary, relocate the air supply to the intake
manifold to the outside of the engine enclosure.
3. Check for air leaks in the pipe between the air inlet
and the inlet to the turbocharger compressor.
Intake Manifold Air Temperature Sensor
and/or the Circuit
1. Allow the intake manifold air temperature sensor
to cool and remove the sensor. Check the reading
for the intake air temperature. If the sensor is
operating correctly, the reading and the ambient
temperature are approximately equal.
2. If the readings are approximately equal, reinstall
the sensor.
3. If the reading is not correct, replace the sensor
with a sensor that is known to be good. Verify that
the fault is rectified.
Insufficient Ambient Air Flow over the
Engine
1. If equipped, check the condition of the cooling fan
and the drive belt.
2. If equipped, check that the cooling fan is operating
correctly.
Reduced Ambient Air Flow through the
Air Charge Cooler
1. Check that the ambient air flow through the air
charge cooler is not obstructed.
2. Inspect the air charge cooler for contamination
and/or bent fins or damaged fins.
3. If necessary, clean the air charge cooler.
4. If necessary, carefully straighten any bent fins on
the air charge cooler.
Reduced Flow of Intake Air through the
Air Charge Cooler
1. Check for contamination in the air pipe that
connects the turbocharger to the air charge cooler.
a. If dirt is found in the air pipe from the
turbocharger to the air charge cooler, check
all of the air inlet pipes upstream of the
turbocharger for leaks.
b. Clean all contaminated air inlet pipes or replace
all contaminated air inlet pipes.
c. Service the air cleaner and replace the air
cleaner element.
2. If a thick oil film is found in the air pipe, inspect the
turbocharger compressor housing. Examine both
the inlet to the turbocharger compressor housing
and the outlet from the turbocharger compressor
for oil.
a. If oil is found in the inlet to the turbocharger
compressor housing, the oil originates from the
engine crankcase breather.
b. If oil is found in the outlet from the turbocharger
compressor housing but oil is not found in
the inlet to the compressor housing, the oil
originates from the seals for the turbocharger
bearings.
SENR9982-01