TROUBLESHOOTING SYMPTOM INDEX

TM 10-3930-638-24&P

3-2. TROUBLESHOOTING SYMPTOM INDEX (cont)

Para/Malfunction Page

FUEL SYSTEM TROUBLESHOOTING (cont)

3-10

3-4/5

Erratic engine operation (surge, misfiring, poor governor regulation) . . . . . . . . . . . . . . . .

3-13

3-4/6

Engine idles imperfectly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-15

3-4/7

Engine does not develop full power or speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-18

3-4/8

Engine smokes black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-19

Engine smokes blue or white.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-4/9

3-19

3-4/10

Fuel not reaching fuel injection pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuel delivered from transfer pump but not to fuel injectors . . . . . . . . . . . . . . . . . . . . . . . .

3-4/11

3-20

Fuel reaching fuel injectors but engine will not start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-22

3-4/12

3-3. ENGINE TROUBLESHOOTING

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. ENGINE HARD TO START OR WILL NOT START

Step 1. Check for correct valve timing in reference to crankshaft timing marks with dial indicator (para 3-5a(1),

step 2).

a. If valve timing is correct, proceed to step 2.

b. If valve timing is not correct, check for sheared key in the cam drive gear or a broken camshaft

(notify general support maintenance) (para 4-2g).

Step 2. Perform compression test of each cylinder (para 3-3, MALFUNCTION 7).

If compression test is satisfactory, check for sheared roll pin on fuel injection pump drive shaft

(para 3-6c) or defective fuel injection pump (notify general support maintenance) (para 4-3b).

2. ENGINE HARD TO START OR WILL NOT START (EXHAUST SMOKE)

Step 1. Check for proper engine timing (para 3-5a).

a. If engine timing is correct, proceed to step 2.

b. If engine timing is not correct, adjust timing (para 3-5a).

Step 2. 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, proceed to step 3.

Step 3. Start engine and listen for excessive valve tappet noise.

If excessive valve tappet noise is heard, stop engine and check for bent push rods (para 3-5j).

3. ENGINE STARTS BUT WILL NOT RUN

Step 1. Check for proper fuel injection pump timing (para 3-5a(3)).

a. If fuel injection pump timing is not correct, adjust timing (para 3-5a(3)).

b. If fuel injection pump timing is okay, proceed to step 2.

3-2