Case IH 3927 – Engine Control Unit (ECU): Fuel pressure control Metering unit: Leakage in high pressure system detected at idle an empty fuel tank

The engine control system has detected that the actual fuel rail pressure has dropped significantly below the commanded target pressure while the engine is idling. This indicates a high-pressure fuel leak or air ingress/fuel starvation caused by an empty or extremely low fuel tank.

• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 315
• Magnum 340
• Steiger series
• Puma
• Optum
• Maxxum
• Axial-Flow 7010
• Axial-Flow 7088
• Axial-Flow 8010
• Patriot Titan 3030
• Patriot Titan 4030

1. 1

   Verify fuel level physically, as a faulty fuel level sender might show fuel in the tank when it is actually empty.

2. 2

   Check for air ingress by installing a clear test line at the inlet of the high-pressure fuel pump and observing for a steady stream of bubbles.

3. 3

   Test low-pressure supply with a pressure gauge between the fuel filter and high-pressure pump (should be minimum 5 bar/72 psi under load).

4. 4

   Inspect primary and secondary fuel filters for blockages, water, or debris.

5. 5

   Perform an injector leak-off (return flow) test to check for worn injectors leaking excessive fuel back to the return line.

1. 1

   Refuel and Bleed

   If the tank was empty or very low, fill the fuel tank and thoroughly bleed the low-pressure and high-pressure fuel systems to purge all trapped air. Clear the fault code and test run the machine.

2. 2

   Resolve Low-Pressure Restrictions

   If pressure tests fail, replace the primary and secondary fuel filters. Inspect and clean the fuel tank pickup tube if debris is found. Replace any leaking Voss O-rings or cracked supply hoses.

3. 3

   Replace Leaking Injectors

   If the injector leak-off test reveals excessive return flow from one or more cylinders, replace the faulty fuel injector(s) and their corresponding connector tubes/seals.

4. 4

   Replace the Fuel Metering Unit (M-PROP)

   If the injectors are fine and there is no air in the system, the Fuel Metering Unit is likely failing to maintain pressure. Remove the old metering unit from the high-pressure pump and install a new one.

5. 5

   Replace the High-Pressure Fuel Pump

   If replacing the metering unit does not resolve the pressure loss, the internal mechanical components of the high-pressure fuel pump are worn out and the entire pump assembly must be replaced.