3114, 3116 and 3126 Engines Caterpillar

Probable Causes

• Poor fuel quality

• Air in fuel

• Binding of the fuel injection control linkage

• Faulty unit injector

• Plugged fuel return

• Incorrect fuel injection timing

• Incorrect valve setting

• Air inlet restriction

• Internal engine problem

Recommended Repairs

Poor Fuel Quality

Ensure that there is good, clean fuel in the tank. When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the engine started misfiring soon after refueling. Refer to Troubleshooting, "Fuel Quality".

Air in the Fuel

Check for air in the fuel system. Refer to Troubleshooting, "Air In Fuel".

Binding of the Fuel Injection Control Linkage

Ensure that the fuel injection control linkage is not binding. Refer to Troubleshooting, "Fuel Injection Control Linkage".

Faulty Unit Injector

Refer to Troubleshooting, "Unit Injector Misfire" and Troubleshooting, "Unit Injector".

Plugged Fuel Return

Remove the fuel return passage check valve. Remove the pressure regulating orifice. Inspect both the check valve and the orifice for signs of blockage.

Incorrect Fuel Injection Timing

Check Fuel Injection Timing. Refer to Systems Operation, Testing And Adjusting.

Incorrect Valve Setting

Check valve adjustment. Refer to Systems Operation, Testing And Adjusting.

Air Inlet Restriction

Check the air inlet system. Also inspect the turbocharger.

Internal Engine Problem

Check for signs of damaged valves, damaged cylinder head gasket, etc.