Case IH 3910 – Engine Control Unit (ECU): Fuel metering unit: Error check for loose contact between metering unit (MeUn) and ECU

The engine controller has detected an intermittent electrical connection, an open circuit, or a loose contact in the circuit between the Engine Control Unit (ECU) and the Fuel Metering Unit. This prevents proper regulation of fuel rail pressure, which can lead to hard starting, surging, or a no-start condition.

• Farmall
• Steiger T4B
• Farmall series (40, 45, 50)
• Puma tractors
• Steiger tractors
• 240 Series Axial-Flow Combines
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Visually inspect the Fuel Metering Unit connector on the high-pressure fuel pump for loose, backed-out, or corroded pins

2. 2

   Trace the wiring harness from the Fuel Metering Unit back to the Engine ECU, looking for chafing, melted insulation, or pinch points

3. 3

   Disconnect the battery and unplug connectors at the metering unit and ECU, then use a multimeter to check for continuity on both wires while wiggling the harness to find intermittent breaks

4. 4

   Measure the internal resistance of the Fuel Metering Unit's solenoid coil (an open circuit or infinite resistance indicates internal failure)

5. 5

   Connect the Case IH Electronic Service Tool (EST) to monitor active fault codes and fuel rail pressure to verify if the metering unit is the culprit after wiring tests good

1. 1

   Prep the Machine

   Turn off the engine, remove the key, and disconnect the battery ground cable to prevent electrical damage.

2. 2

   Clean the Area

   Thoroughly clean the area around the high-pressure fuel pump and the metering unit to prevent dirt from entering the fuel system.

3. 3

   Disconnect

   Unplug the electrical connector from the Fuel Metering Unit.

4. 4

   Remove the Unit

   Remove the mounting fasteners (typically Torx or Allen screws) securing the metering unit to the high-pressure fuel pump.

5. 5

   Extract

   Carefully pull the metering unit straight out of the pump housing. It is sealed with O-rings, so a slight twisting motion may be required.

6. 6

   Prepare the New Part

   Lubricate the O-rings on the new Fuel Metering Unit with clean engine oil or diesel fuel to prevent tearing during installation.

7. 7

   Install

   Push the new unit into the pump housing until it seats fully. Install the mounting screws and tighten them to the OEM torque specification.

8. 8

   Reconnect

   Plug the electrical connector back into the unit and reconnect the battery ground cable.

9. 9

   Clear Codes

   Use the Case IH Electronic Service Tool (EST) to clear the 3910 fault code. Prime the fuel system if necessary, start the engine, and check for leaks and proper operation.