C-12 Generator Set Engine Caterpillar

Note: If this problem occurs under load, refer to the diagnostic procedure Troubleshooting, "Low Power/Poor Or No Response To Throttle".

Probable Causes

• Derated engine

• Cold mode

• Flash file

• Throttle signal

• Turbocharger outlet pressure sensor (intake manifold air), Rated fuel position and/or FRC fuel position

• Fuel supply

• Air inlet restriction

• Exhaust restriction

• Valve adjustment

• Injectors

• Faulty accessory equipment

Recommended Actions

Derate

Connect the Caterpillar Electronic Technician (ET) and check for an active derate event. A derate status flag will appear on Cat ET if an active engine derate is occurring. In order to view active events, go to the "Events" menu under "Diagnostics". Refer to Troubleshooting, "Event Code List" for the specific events for this application.

Cold Mode

Use Cat ET in order to determine the status of cold mode. Cold mode operation may cause the engine to run rough and the engine power may be limited. Cold mode is displayed in the second engine status box on any Cat ET status screen.

Flash File

Verify that the correct flash file has been installed.

Throttle Signal

Use Cat ET in order to monitor the status of the throttle. Observe the throttle position. Verify that the throttle position is smooth from low idle to high idle. The throttle position should reach 100 percent at high idle.

Turbocharger Outlet Pressure Sensor (Intake Manifold Air), Rated Fuel Position and/or FRC Fuel Position

1. During operation at full load, monitor "Fuel Position" and "Rated Fuel Limit" on the Cat ET status screen. If "Fuel Position" does not equal "Rated Fuel Limit" then check the air inlet manifold pressure.

2. Verify that there are no active diagnostic codes that are associated with the turbocharger outlet pressure sensor (intake manifold air) or with the atmospheric pressure sensor.

3. Monitor turbocharger outlet pressure on the Cat ET status screen and atmospheric pressure for normal operation.

Fuel Supply

Check fuel lines for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines.

1. Check the fuel tank for foreign objects which may block the fuel supply. Check for air leaks in the suction line of the fuel pump. Prime the fuel system in order to remove air from the fuel system after you perform the following procedures:
   • Replacing the fuel filters

   • Working on the low pressure fuel supply circuit

   • Replacing fuel injectors

2. Cold weather adversely affects the characteristics of the fuel.

3. Check the fuel pressure during engine cranking. Check the fuel pressure after the fuel filter. 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 Restriction

Replace plugged air filters and/or clean the filters. Leaks in the air inlet system can lower Inlet manifold pressure.

Exhaust Restriction

Check the exhaust system for restrictions and/or for leaks.

Valve Adjustment

Check the valve lash setting.

Injectors

Use Cat ET to determine if any active diagnostic codes are present for the injector solenoids. Perform the "Injector Solenoid Test". Observe that the injector solenoids are being energized on Cat ET. Perform the "Cylinder Cutout Test". Locate the misfiring cylinder. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoids".

Faulty Accessory Equipment

Check attached accessory equipment. Ensure that the accessory equipment is not lugging down the engine.