ARMY TM 9-2815-253-24
AIR FORCE TO 38G1-93-2
MARINE CORPS TM 2815-24/3
Table 3-2. Troubleshooting Continued
TEST OR INSPECTION
13. ABNORMAL ENGINE NOISE.
Step 1. Check for worn tappets.
a. Inspect tappets for wear. Refer to paragraph 3-27. If not worn, do Step 2.
b. Replace worn tappets. Refer to paragraph 3-27.
Step 2. Check for bent pushrods.
a. Replace bent pushrods. Refer to paragraph 3-26.
b. Inspect pushrods for straightness. Refer to paragraph 3-26. If straight, repair or replace engine.
14. DETONATION OR PRE-IGNITION.
Step 1. Check for defective fuel injectors.
a. Remove and test fuel injectors. Refer to paragraph 3-17. If not defective, do Step 2.
b. Replace fuel injectors. Refer to paragraph 3-17.
Step 2. Check for improper fuel pump timing.
Adjust fuel pump timing. Refer to paragraph 3-14. If timing is correct, do Step 3.
Step 3. Check for carbon buildup in compression chambers.
a. Remove cylinder head and inspect for carbon buildup. Refer to paragraph 3-27.
b. Remove carbon and/or replace components as necessary.