PLATFORM REINFORCEMENT GROUP 2S2555 - Caterpillar

Probable Causes
Fuel injector O-ring seals
High-pressure fuel pump
Fuel injector tip
Fuel transfer pump sealNote: For additional information, refer to Special Instruction, REHS3007, "Determining the Cause of Fuel Dilution of Engine Oil".Recommended Actions
Fuel Injector O-ring Seals
Pressurize the engine fuel return line with 700 kPa (100 psi) of air pressure. Listen at each of the valve mechanism covers for an audible indication of air leakage.If leakage is found, remove the injector from the affected cylinder and visually inspect the injector O-ring seals for damage. If damage is found, replace the damaged seals. Install the injector onto the engine and confirm that the repair has resolved the problem. Return the engine to service.If leakage is found and the O-rings are in good repair, there may be a problem with the injector. Replace the injector. Ensure that the new trim files are installed. Refer to Troubleshooting, "Injector Trim File - Install" for details. Use Caterpillar Electronic Technician (ET) to perform a "Fuel System Verification Test". Refer to Troubleshooting, "Injector Solenoid - Test" for details.If the leakage is not located with the previous test procedure, add the appropriate dye to the fuel tanks. Run the engine at high idle for several minutes. Shut down the engine and remove the valve covers. Use a black light to check for traces of dye around each injector.If leakage is suspected for a specific injector, remove the injector from the affected cylinder and replace the damaged seals. Install the injector onto the engine and return the engine to service.High Pressure Fuel Pump
Illustration 1 g01982875
Location of the magnetic plug in the fuel pump adapter (typical example)
(1) Magnetic plug in the fuel pump adapter Note: Perform this test on a cold engine.The fuel pressure in the high-pressure fuel system must be below 1 MPa (145 psi) before this test procedure is performed. Refer to Systems Operation/Testing and Adjusting, "Fuel Rail Pressure - Release" for procedural details. Remove plug (1) from the bottom of the fuel pump adapter. Expect that a small amount of engine oil will drain from the opening. Check the magnetic plug for debris. Clean the plug prior to reinstallation.Use the manual override for the fuel priming pump to run the pump in order to pressurize the fuel system. Allow the pump to run for at least five minutes while you monitor the drain hole in the fuel pump adapter for leakage.Note: Your application may be equipped with a manual switch for the fuel priming pump. If a manual switch is not available, use the override in Cat ET to operate the fuel priming pump.For a pump that is in good repair, fuel may drip intermittently from the adapter drain hole. The leakage must not exceed 6 ml/min (0.2 oz/min). If a continuous stream of fuel is flowing from the drain hole, replace the high-pressure fuel pump. Also replace the in-line high-pressure fuel filter element in the block assembly that is part of the front fuel injection line.Fuel Injector Tip
Use Cat ET to perform the "Cylinder Cutout Test" in order