0335591 JOHNSON SUPPORT, Sensor

Engine Valve Lash, Valve Rotators, Fuel Ratio Control, Set Point, and Low Idle
Check/Adjust
Be sure the engine cannot be started while this maintenance is being performed. To prevent possible injury, do not use the starting motor to turn the flywheel.Hot engine components can cause burns. Allow additional time for the engine to cool before measuring/adjusting valve lash clearance.Operation of Caterpillar engines with improper valve adjustments will reduce engine efficiency. This reduced efficiency could result in excessive fuel usage and/or shortened engine component life.To prevent possible injury, do not use the starter motor to turn the flywheel.
When inspecting the valve rotators, protective glasses or face shield and protective clothing must be worn, to prevent being burned by hot oil or spray.
If a damaged rotator is not replaced, valve face guttering could result in pieces of the valve to fall into the cylinder. This can cause piston and cylinder head damage.Measure the valve lash with the engine stopped. To obtain an accurate measurement, allow at least 20 minutes for the valves to cool to engine cylinder head and block temperature.
For the complete engine valve lash, fuel ratio control, set point, and low idle check/adjust procedures, refer to the Service Manual or contact your Caterpillar dealer.Fuel Injection Nozzles
Test/Clean/Replace
The engine will be damaged if a defective fuel injection nozzle is used because of the shape of fuel (spray pattern) that comes out of the nozzles will not be correct.
Fuel injection nozzles are subject to tip wear as a result of fuel contamination. This damage can cause an increase in fuel consumption, the engine to emit black smoke, misfire or run rough. Inspect, test and replace if necessary.Whenever the engine performs in such a manner that a fuel injection nozzle is suspected of causing irregular running, smoking or knocking, each fuel injection nozzle must be isolated, one at a time, to determine the malfunctioning nozzle. Special tooling is required to remove fuel injection nozzles. Refer to the Service Manual or contact your Caterpillar dealer for fuel injection nozzle testing and cleaning procedures.Turbocharger
Periodic inspection and cleaning is recommended for the turbocharger compressor housing (inlet side) and the aftercooler core. Since the crankcase fumes are ingested through the inlet air system, oil and combustion by-products may collect in these two areas.This buildup, over time, can contribute to loss of engine power, increased black smoke, and overall loss of engine efficiency. This buildup is only a possible contributor to these conditions.Operating the engine until the turbocharger fails can severely damage the turbocharger's compressor wheel and/or the engine. Damage to the turbocharger compressor wheel could allow parts from the compressor wheel to enter the engine cylinder, causing additional damage to the piston, valve, and cylinder head.
Turbocharger bearing failures can cause large quantities of oil to enter the air inlet and exhaust systems. Loss of engine lubricant can result in serious engine damage.When a turbocharger bearing failure is accompanied by a significant engine performance loss (exhaust smoke or engine speed up at no load), DO NOT continue engine operation until the turbocharger is repaired or replaced.
Minor leakage of a turbocharger housing under extended low idle operation will not cause problems as long as no turbocharger bearing failure occurred.Inspect for Proper Operation
Turbocharger components require precision clearances and balancing due to operation at high rotational speeds. Severe Service Applications can accelerate component wear and may suggest the need to Inspect/Repair/Replace the cartridge at reduced intervals to ensure maximum reliability and retention of full core value.The following conditions can indicate severe service operation.* Frequent high altitude operation above 5,000 ft (1525 m).* Arctic operation (regular cold starts at temperatures below 0°C [32°F]).* Extending lubrication and inlet air system maintenance intervals. 1. Remove the exhaust outlet piping (1) and inlet piping (2) from the turbocharger. Visually check for oil leaks.2. Turn the compressor wheel and turbine wheel by hand. The assembly should turn freely. Inspect the compressor wheel and turbine wheel for contact with the turbocharger housing. There should NOT be any visible signs of contact between the turbine or compressor wheel and the turbocharger housing. If there is any indication of contact between the rotating wheel(s) and the housing, the turbocharger should be reconditioned or replaced.3. Use a dial indicator to check end clearance on the shaft. Attach the dial indicator point on the end of turbocharger shaft. Push and pull the other end of the shaft. Note the total dial indicator reading. If the measured end play is greater than the Service Manual specifications, repair or replace the turbocharger. Measured end play less than the minimum Service Manual specifications could indicate carbon build up on the turbine wheel. The turbocharger should be disassembled for cleaning and inspection if the measured end play is less than the minimum Service Manual specifications.4. Check the compressor wheel for cleanliness. If only the blade side of the wheel is dirty, dirt and/or moisture is passing through the air filtering system properly. If oil is found only on the back side of the wheel, an oil seal leak is indicated. The leak may be the result of extended engine operation at low idle, or an inlet air line restriction (plugged air filter).5. Inspect the turbine housing bore for corrosion.6. Clean the turbocharger housing with standard shop solvents and a soft bristle brush.7. Fasten the air inlet piping and the exhaust outlet piping to the turbocharger housing. Refer to the Torque Specification section in this manual for correct fastener torques.Severe Service Operation
Turbocharger components require precision clearances and balancing due to operation at high rotation speeds. Severe Service Applications can accelerate component wear. Engines operating under severe conditions may need more frequent Inspect/Repair/Replace the cartridge intervals to ensure maximum reliability and retention of full core value.The following conditions can indicate severe service operation: * Extended operation at low idle.* Extending lube and air system maintenance intervals.* Frequent hot shutdowns (minimum cool down periods after high load factor operation).Removal and Installation
For removal and installation, or repair/replacement options of turbochargers, see your Caterpillar dealer.Refer to the Service Manual for this