TM 5-6115-400-12
Table 3-3. Troubleshooting--Continued
Malfunction
Probable cause
Corrective action
g. Inoperative fuel injection
g. Repair or replace affected
pump or fuel injection nozzle.
parts (paras 3-32 and 3-33).
6.
Engine Runs Uneven and
a. Governor not operating
a. Refer to higher echelon.
Excessive Vibration
properly.
b. Fuel supply erratic or in-
b. Check fuel stem (para
sufficient.
3-29).
c. Engine operating tempera-
c. Check thermostats (par
ture too low.
3-47).
d. Fuel injection pump malfunc-
d. Replace fuel injection pump
tions.
e. Fuel injection nozzle mal-
e. Replace nozzle (para 3-33).
functions.
7.
Engine detonates
a. A hard metallic knock indi-
a. Check for leaky fuel injec-
cates detonation in one or more
tion nozzles or improper timing
cylinders, the engine must be
of fuel injection pump (para
stopped immediately to prevent
3-32).
serious damage due to the ex-
cessive pressures accompanying
the detonation. Detonation is
caused by the presence of fuel or
lubricating oil in the charge of
air that has been delivered to
the cylinder during the compres-
sion stroke.
8.
Engine emits black smoke
a. Air system clogged.
a. Check engine air intake sys-
from exhaust
tem (para 3-8).
b.
Improper fuel.
b. Drain fuel system and refill
with fuel of proper specification
9.
Engine emits blue
a. Engine operating tempera-
a. Check thermostat (para
ture too low.
3-47).
b. Fuel injection nozzles not
b. Replace nozzles (para 3-33).
operating properly.
10.
Starter will not crank
a. Batteries weak.
a. Check batteries (para 3.62).
engine
b. Cables mad/or connections
b. Tighten all loose connections
loose or corroded.
and clean corrosion from all ter
minals.
c. Starter solenoid switch in-
c. Replace solenoid switch (pare
operative
3-56).
d. Starter brushes worn or not
d. Install new brushes or fit
contacting properly.
brushes to conform to contour of
commutator (para 3-82).
e. DC control circuit breaker in
e. Push DC control circuit
OFF position.
breaker to ON position (para
11.
Starter pinion will not
Grease and/or dirt in start
Refer to direct and general sup-
engage flywheel gear
mechanism.
port maintenance
12.
Low oil pressure
a. Oil pressure relief valve or
a. Clean, replace af-
regulator valve stuck in open
fected part (paras 3-26 and
position.
3-27).
b. Improper lubricant.
b. Fill crankcase with specified
lubricant.
13.
Excessive oil pressure
a. Oil pressure regulating valve
a. Adjust valve to obtain proper
improperly adjusted.
pressure (para 3-27).
b. Improper lubricant.
b. Drain and fill crankcase with
specified lubricant.
3-14
