ENGINE MISFIRES

TM 10-3930-638-24&P

2-9. ENGINE TROUBLESHOOTING (cont)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

3. ENGINE STARTS BUT WILL NOT RUN (cont)

Step 7. (cont)

(1) If fuel is pumped through injection pump, proceed to step 8.

(2) If fuel is not pumped through fuel injection pump, replace it (notify direct support

maintenance).

b. If +24 Vdc is not obtained, troubleshoot electrical system (para 2-19).

c. If fuel is pumped out of disconnected fuel line, proceed to step 8 below.

Step 8. Check for fuel leaks at fuel injector lines.

a. If fuel leaks are observed, tighten or replace lines (para 3-6a; notify direct support mainte-

nance)

b. If fuel lines are okay, proceed to step 9 below.

Step 9. Remove radiator cap, start engine, and observe coolant for gas bubbles.

If gas bubbles rising in coolant are observed, replace cylinder head gasket (para 35g; notify

direct support maintenance).

4. ENGINE MISFIRES

Step 1. Check for incorrect or contaminated fuel in fuel tank (if contaminated, fuel will have

a milky white appearance).

a. If fuel is contaminated, drain fuel tank, clean and fill with correct fuel (para 2 15d (1)) and

replace fuel filters (para 215e and 21 5f).

b. If fuel is not contaminated, proceed to step 2 below.

Step 2. Operate engine for 15 minutes at idle speed.

Carefully and slowly remove radiator cap.

Check coolant temperature using a thermometer be sure that thermometer does not touch any

metal parts of radiator.

Coolant temperature shall be between 175 to 200 degrees F.

a. If coolant temperature is not between 175 to 200 degrees F, remove and test thermostat.

b. If coolant temperature is between 175 to 200 degrees F, proceed to step 3 below.

Step 3. Check for fuel leaks at fuel injector lines.

a. If fuel leaks are observed, tighten or replace lines (para 3-6a; notify direct support mainte-

nance)

b. If fuel lines are okay, proceed to step 4 below.