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Home›Repair guides›Service procedure for NTC 400 BC2 workshop-manual.pdf

Cummins — Service procedure for NTC 400 BC2 workshop-manual.pdf

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Procedure

  1. EXCESSIVE SMOKE WHILE ACCELERATING. Step 1. Check for defective baffles in muffler or severely distorted exhaust piping creating high back pressure. Replace muffler or defective piping (TM 9-2320-281-20). Step 2. Check for dirty turbocharger compressor. Clean compressor (para 3-86). Step 3. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). 2-9
  2. (Cont) Step 4. Check for plugged injector spray holes. Clean injector (para 3-73). Step 5. Check for cracked injector body or cup. Replace defective injector (para 3-6 and 3-94). Step 6. Check for proper injector flow adjustments. Test and adjust injector (para 3-75). Step 7. Check engine valves for proper adjustment. Adjust valves (para 3-94). Step 8. Check for incorrect valve and injector timing. Time valves and injector (para 3-94). Step 9. Check for incorrect AFC or fuel pump calibration. Test and calibrate AFC and fuel pump (para 3-84). Step 10. Check for broken camshaft lobes. Replace defective camshaft (para 3-6 and 3-94). Step 11. Check for bent or broken push rods. Replace defective rods (para 3-6 and 3-94). Step 12. Check for defective cam follower(s). Replace defective follower(s) (para 3-6 and 3-94). Step 13. Check for worn liners or pistons. Replace defective liner or pistons (para 3-6 and 3-94). 2-10
  3. LOW POWER OR LOSS OF POWER. Step 1. Check for defective baffles in muffler or severely distorted exhaust piping creating high back pressure. Replace muffler or defective piping (TM 9-2320-281-20). Step 2. Check for dirty turbocharger compressor. Clean compressor (para 3-86). Step 3. Check for leaks in supply (suction) fuel lines to pump. Tighten all line connectors. Step 4. Check for restricted fuel lines. Purge all lines. Step 5. Check all fuel filters for contamination. Replace or clean filters (including fuel pump screen) (TM 9-2320-281-20). Step 6. Check for plugged injector(s) spray holes. Clean injector(s) spray holes (para 3-73). Step 7. Check for plugged breather tube and breather assembly. Clean tube and breather assembly (TM 9-2320-281-20). Step 8. Check for plugged ASA on fuel pump. Replace ASA (para 3-83). Step 9. Check for plugged injector(s) spray holes. Clean injector(s) spray holes (para 3-73). Step 10. Check for cracked injector body or cup. Replace defective injectors (para 3-6 and 3-94). 2-11
  4. (Cont) Step 11. Check for damaged injector O-rings. Replace O-rings (para 3-72). Step 12. Check for improper injector flow adjustments. Test and adjust injector (para 3-75). Step 13. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 14. Check engine valves for proper adjustment. Adjust valves (para 3-94). Step 15. Check for incorrect valve and injector timing. Time valves and injector (para 3-94). Step 16. Check for defective or miscalibrated fuel pump. Test and calibrate pump (para 3-84). Step 17. Check for scored liners and pistons. Replace defective liners and pistons (para 3-6). Step 18. Check for broken or worn piston rings. Replace defective piston-rings (para 3-5). Step 19. Check for incorrect main bearing clearances. Replace defective bearings and recondition crankshaft as necessary (para 3-6). 2-12
  5. CANNOT REACH GOVERNED RPM. Step 1. Check for defective or maladjusted throttle linkage. Adjust or replace defective linkage (TM 9-2320-281-20). Step 2. Check all fuel filters for contamination. Replace or clean filters (including fuel pump screen) (TM 9-2320-281-20). Step 3. Check high-speed governor setting. Adjust governor setting (para 3-84). Step 4. Check for improper injector flow adjustments. Test and adjust injector (para 3-75). Step 5. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 6. Check for defective or miscalibrated fuel pump. Test and calibrate pump (para 3-84). 2-13
  6. ENGINE ACCELERATES SLOWLY. Step 1. Check for leaks in supply (suction) fuel lines to pump. Tighten all line connectors. Step 2. Check for restricted fuel lines. Purge all lines. Step 3. Check for water in fuel. Drain fuel tank and reservice (TM 9-2320-281-10). Step 4. Check for improper injector flow adjustments. Test and adjust injector (para 3-84). Step 5. Check for blown or leaking head gasket(s). a. Retorque head bolts (Table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 6. Check for plugged ASA on fuel pump. Replace defective ASA (para 3-83). Step 7. Check for defective or maladjusted fuel pump. Test and calibrate pump (para 3-84). 2-14
  7. EXCESSIVE FUEL CONSUMPTION. Step 1. Check air intake and exhaust for restrictions. Remove restrictions (TM 9-2320-281-20). Step 2. Check for external fuel leaks. Repair as necessary. Step 3. Check for improper injector flow adjustments. Test and adjust injector (para 3-75). Step 4. Check for cracked injector body or cup. Replace defective injector (para 3-6 and 3-94). Step 5. Check for damaged injector O-rings. Replace O-rings (para 3-73). Step 6. Check for incorrect valve and injector timing. Time valves and injectors (para 3-94). Step 7. Check for defective or miscalibrated fuel pump. Test and calibrate pump (para 3-84). Step 8. Check for excessive main bearing clearances. Replace defective bearings and recondition crankshaft as necessary (para 3-6). 2-15
  8. POOR ENGINE DECELERATION. Step 1. Check for leaks in supply (suction) fuel lines to pump. Tighten all line connectors. Step 2. Check for restricted fuel lines. Purge all lines. Step 3. Check for damaged injector O-rings. Replace O-rings (para 3-73). Step 4. Check for excessive internal injector leakage. Test and repair injector as necessary (para 3-75). Step 5. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 6. Check for defective or miscalibrated fuel pump (exces
  9. ERRATIC IDLE SPEED. Step 1. Check for leaks in supply (suction) fuel lines to pump. Tighten all line connectors. Step 2. Check for binding or hanging-up throttle input linkage. Lubricate or repair as necessary (LO 9-2320-281-12 and TM 9-2320-281-20). Step 3. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 4. Check for defective or miscalibrated fuel pump (excessive throttle leakage). Test and calibrate pump (para 3-84).
  10. ENGINE DIES. Step 1. Check for defective fuel pump shutoff valve. Perform steps 2a thru 2f of MALFUNCTION 2 to determine status of shutoff valve. Step 2. Check for leaks in supply (suction) lines to fuel pump. Tighten all line connectors. Step 3. Check for fuel blockage in engine fuel lines. Purge all lines. Step 4. Check for external fuel leaks. Repair as necessary. 2-17
  11. (Cont) Step 5. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 6. Check for broken fuel pump drive shaft. Replace pump (para 3-77). Step 7. Check for defective fuel pump. Test, repair, and calibrate fuel pump as necessary (para 3-84).
  12. ENGINE SURGES AT GOVERNED RPM. Step 1. Check for leaks in supply (suction) fuel lines to fuel pump. Tighten all line connectors. Step 2. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 3. Check for defective governor weights. a. Remove fuel pump and governor (TM 9-2320-281-34). b. Disassemble and repair governor as necessary (para 3-82). 2-18
  13. EXCESSIVE OIL CONSUMPTION. Step 1. Check for external oil leaks. Tighten all connectors. Step 2. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 3. Check for broken or worn piston rings. Replace defective piston rings (para 3-6). Step 4. Check for worn or scored liners and pistons. Replace defective liners or pistons (para 3-6).
  14. CRANKCASE SLUDGE. Step 1. Check for dirty oil filter. Replace oil filter (TM 9-2320-281-20). Step 2. Check for defective thermostat (coolant temperature too low). Replace defective thermostat (TM 9-2320-281-20). Step 3. Check for internal water leaks. Disassemble engine and repair as necessary (para 3-6 and 3-94). 2-19
  15. LUBRICATING OIL DILUTION. Step 1. Check for blown or leaking head gasket(s). a. Retorque head bolts (table 3-3). b. Replace defective gasket(s) (para 3-6 and 3-94). Step 2. Check for clogged breather tube and breather assembly. Clean tube and breather assembly (TM 9-2320-281-20). Step 3. Check for cracked injector body or cups. Replace injector (para 3-6 and 3-94). Step 4. Check for defective injector O-rings. Replace O-rings (para 3-73). Step 5. Check for internal fuel leaks. Disassemble heads and repair as necessary (para 3-30). Step 6. Check for defective liner O-rings and crevice seals. Replace defective O-rings and crevice seals (para 3-6 and 3-94).
  16. COOLANT TEMPERATURE TOO LOW. Step 1. Check for defective thermostat. Replace defective thermostat (TM 9-2320-281-20). Step 2. Check for deteriorated thermostat seal lip. Replace seal (TM 9-2320-281-20). 2-20
  17. COOLANT TEMPERATURE TOO HIGH (ENGINE OVERHEATING). Step 1. Check for excessive oil in crankcase (crankshaft oil dipping creating increased friction and parasitic drag on engine). Drain oil to proper level (LO 9-2320-281-12). Step 2. Check exterior of engine for excessive dirt and grease hindering normal heat dissipation. Steam clean engine. Step 3. Check for leaking water pump, hoses, oil cooler, aftercooler, and all external lines. Repair or replace defective parts (TM 9-2320-281-20). Step 4. Check for blown or leaking engine and air compressor head gaskets. a. Replace engine head gasket(s) (para 3-6 and 3-94). b. Replace air compressor head gasket (TM 9-2320-281-34). Step 5. Check for defective thermostat. Replace defective thermostat (TM 9-2320-281-20). Step 6. Check for defective water pump. Replace defective pump (TM 9-2320-281-20). 2-21
  18. LOW IDLE OIL PRESSURE (LESS THAN 10 PSI, [69 KPA]). Step 1. Check for oil dilution. Refer to MALFUNCTION 20 for corrective action. Step 2. Check for coolant overheating. Refer to MALFUNCTION 22 for corrective action. Step 3. Check for low oil level in crankcase. Service crankcase (LO 9-2320-281-12). Step 4. Check for leaks on suction line and fittings. Tighten line or replace gaskets (para 3-54). Step 5. Check oil cooler for restricted coolant flow . Remove and clean cooler (para 3-56). Step 6. Check for defective oil pump high pressure limit valve. Remove pump and replace defective limit valve (para 3-51). Step 7. Check for defective oil pump pressure regulator. Remove pump and replace defective regulator (para 3-51). Step 8. Check oil pump for defective bushing and gears. Replace defective pump. Repair as necessary (para 3-51). Step 9. Check for broken piston cooling nozzle. Replace defective nozzle (para 3-6). Step 10. Check for worn main and rod bearings. Replace defective main and rod bearings (para 3-6). 2-22
  19. LOW OIL PRESSURE AT TORQUE PEAK (LESS THAN 30 PSI, [207 KPA]). NOTE Perform steps 1 thru 9 in MALFUNCTION 23 before proceeding with the following steps. Step 1. Check for clogged oil filter. Replace filter element (TM 9-2320-281-20). Step 2. Check for kinked or clogged or leaking oil pressure signal tube to oil pump. a. Tighten tube connector. b. Clean tube. c. Replace if defective (para 3-6). Step 3. Check for oil leaks on suction line and fittings. Tighten line or replace gaskets (para 3-54). Step 4. Check for worn main and rod bearings. Replace defective main and rod bearings (para 3-6). 2-23
  20. HIGH OIL PRESSURE AT RATED ENGINE RPM (HIGHER THAN 45 PSI, [311 KPA]). Step 1. Check that proper oil viscosity is being used. Drain and service oil system
  21. NO OIL PRESSURE. Step 1. Check for broken oil pump drive shaft or gear turning on shaft. Replace defective pump (para 3-6) and repair as necessary (para. 3-51). Step 2. Check for defective (stuck open) or weak spring in pump pressure regulator. Remove pump and replace regulator (para 3-51).
  22. EXCESSIVE CRANKCASE PRESSURE. Step 1. Check for worn or scored liners or pistons. Replace defective liners or pistons (para 3-6). Step 2. Check for broken or worn piston rings. Replace defective rings (para 3-6). 2-24

Source: manual:NTC 400 BC2 workshop-manual.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.