- Excessive load
- Fuel system leaks
- Fuel quality
- Air inlet restriction
- Exhaust restriction
- Incorrect fuel timing dimension
- Incorrect valve lash setting
- High fuel setting
Ensure that the engine is not operating under an excessive load. Excessive load can be caused by any of the following items:
- High altitude operation
- Low tire pressure (if applicable)
- Parasitic loads
Inspect the fuel system for leaks. Check all lines, hoses, and fittings for leaks. Tighten any loose connections. Check for the presence of fuel in the lubricating oil.
Check the API of the fuel. Refer to Troubleshooting, "Fuel Quality".
Measure air inlet restriction. Refer to Systems Operation, Testing And Adjusting, "Restriction Of Air Inlet And Exhaust". Check the air flow with a water manometer or a vacuum gauge. Connect the gauge to the engine air inlet between the air cleaner and the inlet to the turbocharger. Check the air flow with the engine at full load rpm. The maximum allowable air inlet restriction is 6.25 kPa (25 inches of H2O).
Inspect the exhaust system. Refer to Systems Operation, Testing And Adjusting, "Restriction Of Air Inlet And Exhaust". Check for damage to piping or for a faulty muffler. If no damage is found, check the exhaust system for back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). The maximum exhaust restriction is 10 kPa (40 inches of H2O). Refer to Technical Marketing Information (TMI) for additional data.
Incorrect Fuel Timing Dimension
Ensure that the fuel timing dimension is correct. Make necessary adjustments. Refer to Systems Operation, Testing and Adjusting, "Fuel Timing".
Check the valve lash setting. Refer to Systems Operation, Testing and Adjusting, "Valve Lash".
Ensure that the fuel setting is correct. Make necessary adjustments. Refer to Systems Operation, Testing and Adjusting, "Fuel Setting".