858106Q12 Mercury HOSE ASSEMBLY, Fuel (12 Feet) - With Quick Disconnect Engine End Only

Probable Causes
Diagnostic codes
Electrical connectors
Starting aids
Throttle signal
Injection actuation pressure
Unit injectors
Fuel supply
Air inlet and exhaust systemRecommended Actions
Note: If the symptom only occurs under certain operating conditions (high idle, full load, engine operating temperature, etc), test the engine under those conditions. Troubleshooting the symptom under other conditions can give misleading results.Diagnostic Codes
Check for active diagnostic codes on the Caterpillar Electronic Technician (Cat ET). Troubleshoot any active diagnostic codes before continuing with this procedure.Electrical Connectors
Check for correct installation of ECM connectors J1/P1 and J2/P2 and the unit injector connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect".Starting Aids
Air Inlet Heater (If Equipped)
Ensure that the air inlet heater is programmed to "On". For additional information on the air inlet heater, refer to Troubleshooting, "Air Inlet Heater Circuit - Test".Ether Injection System (If Equipped)
Ensure that the ether injection system is programmed to "On". For additional information on the ether injection system, refer to Troubleshooting, "Ether Injection System - Test".Oil Grade Plugs
Ensure that the correct oil grade plug is installed. The oil grade plug should match with the oil that is installed in the engine. Do not program the "Engine Oil Weight" with Cat ET.Throttle Signal
Monitor the throttle signal on Cat ET. Verify that the throttle signal is stable. Move the throttle from the low idle position to the high idle position in order to verify that the engine is able to reach high idle.Injection Actuation Pressure
Ensure that the injection actuation system is operating properly. Refer to Troubleshooting, "Injection Actuation Pressure - Test".Unit Injectors
Perform the Injector Solenoid Test on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM.
Perform the Cylinder Cutout Test on Cat ET in order to identify any misfiring cylinder(s). Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for more information.Fuel Supply
Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.
Check the fuel tank for foreign objects which may block the fuel supply.
Check for air in the low pressure fuel supply system if any of the following procedures have been performed:
Replacement of the fuel filters
Service on the low pressure fuel supply circuit
Replacement of unit injectors
Purge air from the low pressure fuel supply circuit. Refer to Testing and Adjusting, "Fuel System - Prime" for the correct procedure.Note: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.
Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Refer to Special Publication, SEBD0717, "Diesel Fuels And Your Engine".
Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. Refer to Testing and Adjusting, "Fuel System" 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.Air Inlet and Exhaust System
Check for an air filter restriction. Clean plugged air filters or replace plugged air filters.
Check the air inlet and exhaust system for restrictions and/or leaks. Refer to Testing and Adjusting, "Air Inlet and Exhaust System".