0512037 JOHNSON TUBING

Recommended Actions
Diagnostic Codes and Event Codes
Check for active and/or for logged diagnostic codes on Caterpillar Electronic Technician (ET). Troubleshoot any active codes before continuing with this procedure.Engine Operation
Use Cat ET to check for excessive idle time and/or for a high load factor which would be indicative of poor operating habits. High operating engine speed will also increase fuel consumption.Note: Operation of the engine for long periods at idle speed will cause a deterioration of the internal components of the engine. A deterioration of the internal components of the engine will increase fuel consumption.Note: Engine operation may also be affected by environmental conditions such as wind and snow.Fuel Quality
Note: The quality of the fuel that is used in the engine will affect the rate of fuel consumption. Refer to the Operation and Maintenance Manual.
If the fuel is not of an acceptable quality, drain the fuel system and replace the fuel filters. Refill the fuel system with fuel of an acceptable quality. Refer to the applicable sections in the Operation and Maintenance Manual.
Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.
Check the fuel pressure after the fuel filter while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting for the correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve.Oil Quality
The grade of the lubricating oil must be correct for the ambient conditions. Refer to the Operation and Maintenance Manual.
If the oil is not of an acceptable quality or if the oil has exceeded the service life, drain the oil system and replace the oil filters. Refill the oil system with oil of an acceptable quality. Refer to the Operation and Maintenance Manual.Low Engine Temperature
Operation of the engine below the correct temperature will increase fuel consumption. Check the operation of the water temperature regulator. If necessary, replace the water temperature regulator. Refer to Disassembly and Assembly.Air Inlet and Exhaust System
Check the air filter restriction indicator, if equipped. Clean plugged air filters or replace plugged air filters. Refer to the Operation and Maintenance Manual.
Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Systems Operation/Testing and Adjusting.Low Inlet Air Pressure
Check the pipe from the outlet of the turbocharger compressor to the inlet manifold for leaks. If necessary, repair any leaks.
Check for the correct operation of the wastegate in the turbocharger. Refer to Systems Operation/Testing and Adjusting.
If the turbocharger is suspected as being faulty, replace the turbocharger. Refer to Disassembly and Assembly.Excessive Valve Lash
Excessive valve lash can cause a reduction of the flow of combustion air into the engine. Reduced flow of combustion air will increase the fuel consumption rate. Check the valve lash and reset the valve lash, if necessary. Refer to Systems Operation/Testing and Adjusting.Failure of the Primary Speed/Timing Sensor
If the primary speed/timing sensor fails, the engine will continue to operate using the signal from the secondary speed/timing sensor on the fuel rail pump. Timing differences between the secondary speed/timing sensor and the primary speed/timing sensor may cause an increase in fuel consumption. If necessary, replace the primary speed/timing sensor. Refer to Disassembly and Assembly.