ARMY TM 9-2815-255-24 AIR FORCE TO 38G1-95-2 MARINE CORPS TM 2815-24/4 TABLE 3-2.  Troubleshooting - Continued MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 15.  ENGINE MAKES A GAS LEAKING NOISE. Step 1.  Check for loose or damaged exhaust manifold. a. Inspect for damage and loose attaching hardware.  If not damaged or loose, do step 2. b. Tighten or replace exhaust manifold.  Refer to paragraph 3-14.3. Step 2.  Check for loose fuel injection nozzles. a. Inspect fuel injection nozzles for looseness.  If not loose, do step 3. b. If loose, replace washers and tighten fuel injection nozzles.  Refer to paragraph 3-29. Step 3.  Check for damaged cylinder head gasket. a. Inspect area around cylinder head gasket for evidence for gas leakage. b. Remove cylinder head and replace gasket.  Refer to paragraph 3-34. 16.  DETONATION OR PRE-IGNITION. Step 1.  Improper fuel injection pump timing. Adjust fuel injection pump timing.  Refer to paragraph 3-28.  If timing is correct, do step 2. Step 2.  Defective fuel injector nozzles. a. Test fuel injector nozzles.  Refer to paragraph 3-29.3.  If not defective to step 3. b. Replace fuel injector nozzles.  Refer to paragraph 3-29. Step 3.  Carbon build-up in compression chamber. a. Remove cylinder head and inspect for carbon build-up.  Refer to paragraphs 3-34.1.  and 3-34.4. b. Remove carbon and/or replace components as necessary. 3-13