What is SPN 5397 FMI 31 CUMMINS & How to Solve It?

What is SPN 5397 FMI 31:

SPN 5397 FMI 31 in Cummins engines refers to a low voltage issue in the Fuel Pressure Regulator Circuit. FMI 31 indicates that the voltage from the fuel pressure regulator is lower than expected, which could cause poor fuel pressure control and affect engine performance.

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Why This Happens:

• Faulty fuel pressure regulator.
  
• Damaged wiring or short circuit in the regulator circuit.
  
• Loose or corroded connectors in the fuel pressure regulator circuit.
  
• Low fuel pressure due to a failing fuel pump.
  
• ECM failure to properly interpret the fuel pressure regulator signal.
  
  

How to Fix It:

1. Inspect the fuel pressure regulator and its wiring for damage.
   
2. Test the voltage and resistance from the regulator to ensure proper operation.
   
3. Clean or replace connectors if corroded or loose.
   
4. Replace the faulty fuel pressure regulator if necessary.
   
5. Check the fuel system for low pressure or a failing fuel pump.
   
   

How to Avoid It Before It Happens:

• Perform routine maintenance on the fuel pressure regulator and associated wiring.
  
• Ensure connectors are free of corrosion and moisture.
  
• Maintain proper fuel pressure and monitor the fuel system regularly.
  
• Replace fuel filters at recommended intervals.
  
• Clue’s Fuel Management services help monitor fuel pressure systems and identify issues before they affect engine performance.