TM 10-3930-659-20 Table 4-1.  Mechanical Troubleshooting (Con't). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Step 5. Check engine Idle speed (see STE/ICE-R Test G04). WARNING Diesel  fuel  is  combustible.    DO  NOT  smoke  or  allow  open  flame  near  fuel  tank. Failure to follow this warning will result in death or serious Injury to personnel.  If you are burned, Immediately seek medical aid. Step 6. Perform fuel system tests (see STE/ICE-R Tests NG31 and GO10). Step 7. Check fuel injection pump metering valve for sticking. Lightly tap fuel injection pump housing with soft hammer.  If engine starts, notify Direct Support Maintenance. Step 8. Inspect cylinder head valve for proper clearance (see paragraph 5-1). Adjust cylinder head valves (see paragraph 5-1). WARNING Before attempting to remove or replace any part of exhaust system, allow exhaust system to cool.  Failure to follow this warning will result in serious burns. Step 9. Inspect muffler for restrictions. Remove  muffler  (see  paragraph  5-27)  and  run  engine  (see  TM  10-3930-659-10).    If  engine operation is normal, replace muffler (see paragraph 5-27). Step 10. Check fuel injection pump static timing (see paragraph 5-26). Adjust fuel injection pump static timing (see paragraph 5-26). If engine still does not develop full power, notify Direct Support Maintenance. 4. ENGINE EMITS EXCESSIVE BLACK OR GRAY EXHAUST SMOKE. WARNING If NBC exposure is suspected, all air filter media should be handled by  personnel  wearing  protective  equipment.    Consult  your  NBC Officer    or    NBC    NCO    for    appropriate    handling    or    disposal procedures. Step 1. Check for lit engine air filter indicator light. If engine air filter indicator light is lit, clean or replace air cleaner (see paragraph 5-9). 4-11