Resolving Low Rail Pressure Issue: Doosan Engine Code P0087 Guide

To address the issue indicated by the fault code P0087 SPN 520196 FMI 1 on a Doosan engine, which is related to “rail pressure physical range low,” you can follow these systematic steps:

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Diagnostic Guide for Doosan Engine Code P0087

Reason for the Fault Code:

The error occurs when the rail pressure falls below a certain threshold relative to the engine speed.

Effects of the Fault:

• SVS Torque limit is set to 0%.

Steps to Diagnose and Solve the Issue:

1. Condition for Running Diagnostic:
   • Ensure the engine is running to perform the diagnostic tests.
2. Condition for Setting the Fault Code:
   • The fault code is set when the rail pressure is below the required limit based on the engine speed.
3. Condition for Clearing the Fault Code:
   • The fault code will clear when the rail pressure no longer falls below the limiting value based on the engine speed.
4. Diagnostic Checklist:
   • Check Fuel Supply: Inspect the fuel lines for leaks, kinks, or blockages that could restrict fuel flow.
   • Fuel Filter Inspection: Replace the fuel filter if it’s dirty or clogged as it can restrict the flow of fuel to the engine.
   • Inspect Fuel Pump Operation: Ensure the fuel pump is operating correctly and delivering the necessary fuel pressure to the rail.
   • Check for Air in the Fuel System: Air in the fuel system can cause low pressure issues. Bleed the system if necessary.
   • Fuel Pressure Sensor Check: Verify the accuracy of the fuel pressure sensor. A faulty sensor may report incorrect pressure readings.
   • Examine Engine Control Module (ECM) Data: Use diagnostic software to monitor real-time data from the ECM for any anomalies in engine performance that could be related to fuel pressure.
5. Testing and Adjustments:
   • Rail Pressure Testing: Using a suitable diagnostic tool, check the actual rail pressure to ensure it aligns with the required specifications.
   • Adjustments: If discrepancies are found in fuel pressure, adjustments might be needed either in the fuel pump output or the pressure regulator settings.
6. Confirm Resolution:
   • After making adjustments or repairs, run the engine and monitor the rail pressure to confirm that it stays within the specified range during various engine speeds.
   • Recheck the system to ensure no fault codes reappear and that the engine operates correctly under load.
     

     Step	Inspection	Standard Value	YES	NO
     1	P0087 is raised on diagnostic tool?	Step2
     2	Check the battery voltage Battery voltage is normal?	Step4	Step3
     3	Change battery & Engine running Problem fixed?	Problem fixed	Step4
     4	Check FIE system related faults or malfunction If any, please refer to related manual & take action Problem fixed?	Problem fixed	Step5
     5	Check if there is any leak in the FIE system If there is any leak, fix or change that part Problem fixed?	Problem fixed	Step6
     6	Change all FIE system (CP-> Rail ->HPC & Injector) For each part change, run engine and then check if the fault disappear or not before next part change Problem fixed?	Problem fixed	Call Hot line

By following these detailed steps, you should be able to diagnose and resolve the low rail pressure issue represented by Doosan engine code P0087. Always ensure that all work is performed safely and that you are equipped with the correct tools and knowledge before starting any repair.