Case IH 3919 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Fuel pressure control Metering unit: Too low fuel rail pressure with MeUn Control with empty Tank

The engine management system has detected that the fuel rail pressure has dropped below the minimum required threshold while the Fuel Metering Unit (MeUn) is actively trying to control pressure, specifically under conditions where the system registers the fuel tank as empty or critically low.

• Magnum
• Steiger
• Puma
• Maxxum
• Farmall
• Case construction equipment (loaders, backhoes)

1. 1

   Verify Fuel Level: Physically verify the fuel level in the tank. Do not rely solely on the dash gauge, as a faulty fuel level sender can cause the system to run dry while reading full.

2. 2

   Check for Low-Pressure Supply Restrictions: Inspect the fuel pre-filter, primary/secondary fuel filters, and the fuel tank pickup tube for debris or blockages.

3. 3

   Test for Air Ingress: Install a test line constructed with clear tubing at the inlet of the high-pressure Bosch fuel injection pump. Run the engine and observe for air bubbles (a steady stream indicates an air leak in the low-pressure supply side).

4. 4

   Measure Low-Pressure Fuel Supply: Install a pressure gauge between the fuel filter and the high-pressure pump. Pressure should be a minimum of 5 bar (72 psi) under load. At the lift pump, ensure pressure does not drop below 0.276 bar (4.0 psi).

5. 5

   Inspect Fittings: Check all Voss O-ring fittings and fuel lines for signs of weeping fuel or air leaks.

1. 1

   Refuel and Bleed

   If the tank was empty or extremely low, fill the tank and perform a complete fuel system bleed procedure to purge all air from the low and high-pressure circuits. Clear the code and test run.

2. 2

   Replace Fuel Filters

   If the tank was not empty, replace the primary (water separator) and secondary fuel filters, as a restricted filter will starve the high-pressure pump and trigger this code.

3. 3

   Resolve Air Leaks

   If the clear-tube test revealed air ingress, trace the low-pressure lines back to the tank. Replace any damaged lines, cracked filter housings, or degraded Voss O-ring fittings.

4. 4

   Clean the Fuel Tank

   If fuel pressure is still low and filters are new, drain and clean the fuel tank. Inspect the bottom and sidewalls for algae/sludge, and clean the pickup tube screen.

5. 5

   Replace the Fuel Metering Unit (FCA/MPROP)

   If the low-pressure supply is verified to be solid (no air, >72 psi at the high-pressure pump inlet), the Fuel Metering Unit on the high-pressure pump is likely failing to command the correct pressure. Replace the unit.

6. 6

   Replace the Fuel Pressure Sensor

   If the engine runs perfectly fine but the code persists, the common rail fuel pressure sensor may be sending inaccurate low-pressure readings to the EDC. Replace the sensor.