ENGINE STALLS FREQUENTLY OR DOES NOT DEVELOP FULL POWER

TM 10-3930-638-24&P

3-3. ENGINE TROUBLESHOOTING (cont)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

5. ENGINE STALLS FREQUENTLY OR DOES NOT DEVELOP FULL POWER

Step 1. Check for proper engine timing and valve tappet clearance adjustment (para 3-5a).

a. If engine timing and valve tappet clearance adjustment is not okay, adjust (para 3-5a).

b. If engine timing and valve tappet clearance adjustment is okay, proceed to step 2.

Step 2. Check fuel injection pump timing and speed adjustments (para 3-5a(3)).

a. If fuel injection pump timing and speed adjustments are not okay, adjust as described in

b. If fuel injection pump timing and speed adjustments are okay, proceed to step 3.

Step 3. Perform compression test of each cylinder (para 3-3 MALFUNCTION 7).

If compression test is satisfactory, test fuel injector nozzles before reinstalling on engine (notify

general support maintenance) (para 4-3a). If fuel injector test is satisfactory, check for camshaft

installed one tooth out of time or a defective fuel injection pump (notify general support

maintenance) (para 4-2g or 4-3b).

6. ENGINE KNOCKS

Start engine and listen for chucking or pounding sound at low speed, which disappears as engine

Step 1.

speed is increased.

a. If chucking or pounding sound is heard at low speed and disappears as engine speed is increased,

check flywheel for looseness or damage (notify general support maintenance) (para 4-2e).

b. If chucking or pounding sound is not heard, proceed to step 2.

Start engine and listen for a sharp metallic sound which increases as engine speed increases.

Step 2.

Crack (open) the injector line to each cylinder, one at a time, to check if the knock stops or decreases.

a. If the knock stops or decreases, check for defective rod bearing on affected cylinder (notify

general support maintenance) (para 4-2f).

b. If the knock increases, check for defective piston pin (notify general support maintenance)

c. If knock is not heard, proceed to step 3.

Step 3. Start engine and listen for a thudding sound which increases as engine speed increases.

a. If thudding sound is heard which increases as engine speed increases, check main bearings for

wear or damage (notify general support maintenance) (para 4-2d).

b. If thudding sound is not heard, proceed to step 4.

Step 4.

Start engine and listen for one thudding sound when increasing engine speed and one thud when

decreasing speed.

Check camshaft and crankshaft for excessive end play (notify general support maintenance)

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