ABNORMAL ENGINE OPERATION
1. Check the engine coolant temperature gage and, if
the temperature does not reach 160-185° "F (71-85 "°C)
Check the compression pressures (consult the Hard
while the engine is operating, consult the Abnormal
Engine Coolant Temperature chart.
8. Incorrect operation of the engine may result in
2. Check engine fuel spill back and if the return is less
excessive loads on the engine. Operate the engine
than specified, consult the No Fuel or Insufficient Fuel
according to the approved procedures.
9. Refer to Item 13 on Chart 4.
3. Check the injector timing and the position of the
injector racks. If the engine was not tuned correctly,
10. Check the ambient air temperature. A power
perform an engine tune-up. Erratic engine operation
may also be caused by leaking injector spray tips.
depending upon injector size, for each 10 °F (6 °C)
Replace the faulty injectors.
temperature rise above 90 °F (32 °C) will occur.
Relocate the engine air intake to provide a cooler source
Check the compression pressures within the
cylinders and consult the Hard Starting chart if
11. Engines lose horsepower with increase in altitude.
compression pressures are low.
The percentage of power loss is governed by the
altitude at which the engine is operating.
5. Erratic engine operation may be caused by governor-
to-injector operating linkage bind or by faulty engine
Clean the air box and drain tubes to prevent
Perform the appropriate engine tune-up
accumulations that may be picked up by the air stream
procedure as outlined for the particular governor used.
and enter the engine's cylinders.
Perform an engine tune-up if performance is not
Inspect the blower oil seals by removing the air inlet
housing and watching through the blower inlet for oil
radiating away from the blower rotor shaft oil seals while
Check the engine gear train timing. An improperly
the engine is running. If oil is passing through the seals,
timed gear train will result in a loss of power due to the
overhaul the blower.
valves and injectors being actuated at the wrong time in
the engine's operating cycle.
Check for a defective blower-to-block gasket. Replace
the gasket, if necessary.
6. Perform a Fuel Flow Test and, if less than the
specified fuel is returning to the fuel tank, consult the No
12. Refer to Item 1 of this chart.
Fuel or Insufficient Fuel chart.
13. Check injector timing and the position of each
7. Check for damaged or dirty air cleaner and clean,
injector rack. Perform an engine tune-up, if necessary.
repair or replace damaged parts.
If the engine is correctly tuned, the erratic operation may
be caused by an injector check valve leaking, spray tip
Remove the air box covers and inspect the cylinder liner
holes enlarged or a broken spray tip. Replace faulty
ports. Clean the ports if they are over 50% plugged.
Check for blower air intake obstruction or high exhaust
back pressure. Clean, repair or replace faulty parts.