FILTER ELEMENT-BREATHER 9R9925 - Caterpillar

Probable Causes
Fuel injector seals
Fuel injector tip
Fuel transfer pump sealNote: For additional information, refer to , REHS3007, "Determining the Cause of Fuel Dilution of Engine Oil".Recommended Actions
Table 1
Troubleshooting Test Steps Values Results
1. Check the Fuel Injector O-ring Seals
A. Look for signs of damage to the seals for the fuel injectors. Pressurize the engine fuel return line with 700 kPa (100 psi) of air pressure. At each of the valve mechanism covers listen for air leaking.
Injector
Result: A leak was not heard.
Proceed to the Test Step 2.
Result: A leak was heard.
Remove the injector and inspect the injector O-ring seals.
Replace damaged seals and retest.
Result: A leak was heard and the O-rings are OK.
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.
2. Check the Fuel Injector Tip
A. Look for signs of damage to the fuel injector. Check the fuel injector tip for cracks or breakage.
Injector
Result: The fuel injector is OK.
Proceed to Test Step 3.
Result: The fuel injector is not ok.
Make the necessary repairs.
3. Check the Fuel Transfer Pump
A. Ensure that the weep hole for the pump is not plugged.
B Check for fuel leakage around the shaft seal for the fuel transfer pump.
Seal
Result: The weep hole was plugged.
Clear the plug.
Result: The pump is leaking fuel.
Repair the pump or replace the pump.