TM 5-3825-225-14&P
Table 5-1. Direct Support and General Support Troubleshooting ( Con’t).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
_________
WARNING
Keep hands away from the spray. The working pressure will cause fuel to penetrate the
skin.
Step 2. Check the high pressure fuel lines for obstructions. Disconnect each high pressure fuel line one at a
time from the injector nozzles and crank the engine.
If fuel does not flow from the fuel line or if the flow is retarded, replace the fuel line.
Step 3. Check the injector nozzles. Disconnect the high pressure fuel line at both ends and remove the injector
nozzle. Connect the fuel line to the injector nozzle and pump. Turn the nozzle away from the engine.
Loosen the high pressure fuel lines from the other injector nozzles to prevent fuel from entering the
cylinders. Crank the engine until fuel sprays from the removed nozzle. Do this in turn with each
nozzle.
If the spray is wet, or variable, or to one side, or if the nozzle dribbles fuel, replace the nozzle.
Prime the fuel system (see paragraph 5-22).
Step 4. Check fuel injector pump and valve timing. Correct it as necessary (see paragraph 5-20).
Step 5. Check cylinder compression. Disconnect lead wire from throttle control solenoid (6, Appendix F, Figure
69). Disconnect the high pressure fuel line from the no. 1 injector nozzle. Disconnect the return fuel
line from no. 1 injector nozzle. Remove the no. 1 injector nozzle and insert a diesel engine
compression gage. Crank the engine and note reading on compression gage. Repeat procedure for
other cylinders. If there is more than 25 psi (172 kPa) difference between cylinders, check the cylinder
in question.
Remove the injector nozzle and add approximately a tablespoonful of clean crankcase oil. If
the compression pressure increases, check the piston rings for damage. If the compression
pressure remains the same, check the valves and head gasket for damage.
Step 6. Disassemble the engine and check the piston rings, valves, valve seats, and cylinder bores.
Replace any of the above parts as necessary.
3. ENGINE DOES NOT DEVELOP FULL POWER.
Step 1. Check the fuel injector pump (see Malfunction 2, step 1).
Step 2. Check the fuel injector pump timing (see paragraph 5-20).
Step 3. Check cylinder compression (see Malfunction 2, step 5).
4. EXHAUST IS SMOKY.
Step 1. Check the fuel injector pump (see Malfunction 2, step 1).
Step 2. Check injector nozzles (see Malfunction 2, step 3).
Step 3. Check fuel injector pump and valve timing and correct as necessary (see paragraph 5-20).
Step 4. Check cylinder compression (see Malfunction 2, step 5).
Step 5. Disassemble the engine and check for incorrect tappet adjustment, sticking valves, worn cylinder
bores, pitted or worn valves and/or valve seats, broken or worn piston rings, and piston seizure / pick
up.
Replace any of the above parts as necessary.
5-3
