Case IH 3236 (F-518159-31) – Engine Control Unit (ECU) / ECM: Number of injections is limited by system

The ECU monitors the difference between the requested number of fuel injections and the current capability of the high-pressure fuel injection system to fulfill that request. The fault is triggered if the difference between the number of requested injections and actual injections reaches five injections, or if the number of requested injections is more than the allowed injections for the current battery voltage and engine speed.

• VESTRUM CVX
• Magnum Series 235-340 (Series 4)
• Magnum 370
• Magnum 380
• Puma Series
• Steiger 280
• Steiger 330
• Steiger 335
• Steiger 350
• Steiger 550
• Farmall 35A
• Farmall 40A
• Farmall 90C-120U
• Maxxum 110
• Maxxum 115
• 240 Series Axial-Flow Combines

1. 1

   Verify Power Supply: Check that the tractor battery power supply has not been connected to an external power supply (like a jump box or charger). If an external power supply is connected, disconnect it and test the system for normal operation.

2. 2

   Check Operating Voltage: Check the battery voltage on the instrument cluster. Start the engine and run it at 2000 RPM to ensure the alternator is charging properly and voltage is stable.

3. 3

   Fuel System Capability Check: If voltage is correct, monitor the actual vs. desired fuel rail pressure to see if the high-pressure pump is failing to keep up with the commanded injections.

1. 1

   Isolate Voltage Issues

   Disconnect any external power sources. Test the battery and alternator. If voltage drops significantly under load, repair the charging system first.

2. 2

   Inspect for Leaks

   Check the high-pressure fuel lines, fuel rail, and injector connections for any physical fuel leaks that would cause a loss of pressure/quantity balance.

3. 3

   Test the Fuel Rail Pressure Sensor

   Verify the sensor's output voltage matches the mechanical pressure. A faulty sensor can report inaccurate pressure drops, causing the ECU to limit injections.

4. 4

   Replace the High-Pressure Fuel Pump

   If the electrical system is sound, there are no leaks, and the pressure sensor is accurate, the high-pressure fuel pump is likely worn internally and unable to maintain the required fuel volume (quantity balance). Replace the pump.