NUT 9M3770 - Caterpillar

Introduction
Troubleshooting can be difficult. To make a repair to a problem, refer to the possible cause and the corrective action. The most common problems are identified in this troubleshooting manual. The symptoms, causes, and guidance for solving the problems are given.The list of problems, causes and corrections will only give an indication of the location of a possible problem. There is also a list that shows some of the repairs that are required.Sometimes additional repair work is required beyond the repair which is recommended. Frequently, a problem does not exist in isolation. The problem can be a result of wear or of damage to several parts which operate together as part of a system.Service personnel may remember similar complaints which were corrected by a previous method of troubleshooting. A similar complaint can have a different cause.Get a good description of the problem from the operator and/or the person that owns the vehicle. Knowing the details of the problem can save time. This will make the repair job faster and easier.All possible problems and the probable causes cannot be listed. The technician must follow a logical process of eliminating possible causes and of identifying the specific causes of the problems.Troubleshooting The Fuel Injection Nozzles On The Engine
Note: Be careful when you are handling the fuel injection nozzles in order to prevent damage to the orifices, the threads, and other surfaces. When a fuel injection nozzle is installed, make sure that all surfaces and threads are clean.Only personnel that have the proper training should disassemble the fuel injection nozzles. Only personnel that have the proper training should perform repairs to the fuel injection nozzle.Replace the fuel injection nozzle if the fuel injection nozzle cannot be adjusted in order to operate correctly.Refer to Specifications, "Fuel Injection Nozzles" for additional information. The engine is difficult to start or the engine runs rough.
Probable Cause
The fuel injection nozzle does not seal correctly in the cylinder head.Make sure that the gaskets, the insert and the mating surface of the cylinder head are clean. Make sure that the fuel injection nozzle is tightened to the correct torque in the threaded hole of the cylinder head.
There is debris on the mating surface of the cylinder head with the gaskets or the insert. Make sure that extra gaskets were removed from the threaded recess in the cylinder head for the fuel injection nozzle.Remove any extra gaskets or debris.
The connections of the high pressure fuel line leak.Tighten the fittings of the high pressure fuel line.
The fuel injection nozzle does not operate correctly.Make sure that the components of the fuel injection nozzle are tightened to the correct torques. Make sure that the gaskets and the insert are positioned correctly. Test the fuel injection nozzle on a nozzle tester in order to measure the pressure setting.
The incorrect fuel injection nozzle is installed.Make sure that all fuel injection nozzles are the correct replacement parts for the engine. Refer to the Parts Manual for the correct replacement part. The engine exhaust has too