Massey Ferguson E9151 – Engine Control Unit (ECU): Fuel rail pressure limiter

The pressure regulating valve (PRV) is failing to regulate pressure correctly. This can be due to the valve being recognized as OPEN (stuck open, bypassing fuel back to the tank and causing a loss of rail pressure - E 9151 31) or sticking (causing erratic fuel pressure - E 9151 7).

• Massey Ferguson 8600 Series
• Massey Ferguson 8650
• Massey Ferguson 8690
• Massey Ferguson 5400 Series
• Massey Ferguson 6400 Series
• Massey Ferguson 7400 Series
• Massey Ferguson 8400 Series
• Massey Ferguson 5600 Series
• Massey Ferguson 6700 Series
• Massey Ferguson 7600 Series
• Massey Ferguson 7700 Series
• Massey Ferguson 8700 Series
• Massey Ferguson 9500 Series
• Massey Ferguson 9800 Series

1. 1

   Check the fuel level in the tank to ensure the system is not simply starving for fuel.

2. 2

   Inspect all low-pressure and high-pressure fuel lines for damage, kinks, or leaks.

3. 3

   Check fuel filter pressure to ensure a clogged fuel filter is not starving the high-pressure pump.

4. 4

   Test the Rail Pressure Sensor by verifying the 5V electrical connection from the ECM to ensure the sensor isn't falsely reporting a pressure drop.

5. 5

   Perform a bypass test by inspecting the return line coming off the PRV at the back of the fuel rail. If the valve is stuck open (E 9151 31), it will excessively bypass fuel back to the tank.

1. 1

   Cool engine

   Turn off the tractor and allow the engine to cool completely to ensure all residual high pressure in the fuel rail has dissipated.

2. 2

   Locate PRV

   Locate the Fuel Rail Pressure Relief Valve (PRV), which is threaded into the end of the high-pressure fuel rail.

3. 3

   Disconnect return line

   Disconnect the fuel return line attached to the PRV.

4. 4

   Remove PRV

   Carefully unscrew and remove the faulty PRV from the fuel rail.

5. 5

   Install new PRV

   Install the new PRV. Torque wrench setting figures given in the workshop manual must be strictly adhered to when fitting the new valve to prevent rail damage or high-pressure leaks.

6. 6

   Reconnect return line

   Reconnect the fuel return line.

7. 7

   Bleed fuel system

   Bleed the fuel system. AGCO Sisu engines feature a hand pump and an overflow pipe from the filter to assist with bleeding the low-pressure side of the system.

8. 8

   Verify repair

   Clear the fault codes using the instrument panel or a diagnostic tool, start the engine, and verify that rail pressure is stable and there are no leaks.