DETROIT DIESEL 53
Trouble Shooting En gine 15.2
Chart 3 (Cont'd.)
ABNORMAL ENGINE OPERATION (Cont'd.)
Check the compression pressures; if found low, consult
3. Check the injector timing and the position of the
the Hard Starting chart.
injector racks. If the engine was not tuned correctly,
perform an engine tune-up. Erratic engine operation
9. Incorrect operation of the engine may result in
may also be caused by leaking injector spray tips.
excessive loads on the engine. Operate the engine
Replace the faulty injectors.
according to the approved procedures outlined in the
4. Check the compression pressures within the cylinder
and consult the Hard Starting chart if compression
10. Refer to Item 13 on Chart 4.
pressures are low.
11. Check the ambient air temperature. A power
5. Erratic engine operation may be caused by governor-
to-injector operating linkage binding or by faulty
depending upon injector size, for each 10F.
adjustments when performing the engine tune-up.
temperature rise above 90F. will occur. Relocate the
These items may be corrected by performing the
engine air intake to provide a cooler source of air.
appropriate engine tune-up procedure as outlined for the
12. Engines lose horsepower with increases in altitude.
The percentage of power loss is governed by the
6. The engine should be tuned whenever performance
altitude at which the engine is operating.
is not satisfactory.
13. Check oil bath air cleaners to see that they have
Check the engine gear train timing. An improperly
been filled to the proper level with the same viscosity
timed gear train will result in a loss of power due to the
lubricating oil that is used in the engine.
valves and injectors being actuated at the wrong time in
Clean the air box and drain tubes to prevent
the engine's operating cycle.
accumulations that may be picked up by the air stream
and enter the engine's cylinders.
7. Perform a Fuel Flow Test and, if less than .6 gallon
per minute is returning to the fuel tank, consult the No
Inspect the blower oil seals by removing the air inlet
Fuel or Insufficient Fuel chart.
housing and watching through the blower inlet, for oil
radiating away from the blower rotor shaft oil seals while
8. Check for damaged or dirty air cleaners and clean,
the engine is running. If oil is passing through the seals,
repair or replace damaged parts.
overhaul the blower.
Remove the air box covers and inspect the cylinder liner
Check for a defective blower-to-cylinder block gasket.
ports. If the ports are over 50% plugged, clean them.
Replace the gasket if necessary. If the blower has been
removed, install a new gasket.
When it is determined that the engine is not getting an
adequate supply of air into the cylinders, resulting in
14. Refer to Item 1 of this chart.
cleaners, inadequate air supply to the engine
15. Check injector timing and the position of each
compartment cylinder liner ports over 50% plugged,
injector rack. If the engine was not tuned-up correctly,
blower air intake obstructed or high exhaust back
perform an engine tune-up. If the engine is correctly
pressure. The faulty parts should be cleaned, repaired
tuned, the erratic operation may be caused by an
injector check valve leaking, spray tip holes enlarged, or
a broken spray tip. Replace all injectors found faulty.
1970 General Motors Corp. October, 1970