Case IH 3357 – Engine Control Module (ECM) / EDC: Misfire in Multiple Cylinders - Too Many Misfires

The engine control system has detected that multiple cylinders are failing to ignite and combust properly, which is typically caused by fuel starvation, air in the fuel system, or failing fuel injectors.

• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 315
• Magnum 340

1. 1

   Check for fuel inlet / return restriction: Ensure the vacuum between the inlet of the fuel lift pump and the tank does not exceed 50.8 mm (2 inches) of Hg.

2. 2

   Check for air ingress: Inspect the fuel supply lines for air leaks that could cause startup failures and misfires.

3. 3

   Test fuel delivery performance: Verify the flow and operation of the gear supply (lift) pump.

4. 4

   Check high-pressure pump pressure: Test the pressure control of the high-pressure pump inlet regulator and the fuel supply pressure to the high-pressure pump.

5. 5

   Check injector leakage: Measure the fuel leakage rate from the electronically controlled injectors to isolate the cause of excessive fuel bypass.

6. 6

   Provide an alternate fuel supply: Run the engine from an alternate, clean fuel source to definitively diagnose or rule out fuel tank/inlet problems.

1. 1

   Test the System First

   Always test the fuel system as described above before removing the BOSCH fuel injection pump or injectors for repair.

2. 2

   Address Restrictions

   If vacuum limits are exceeded, replace the fuel filters and clear any blockages in the fuel lines.

3. 3

   Replace Faulty Injectors

   If diagnostic tests isolate excessive leakage or failure to the fuel injectors, they must be replaced.

4. 4

   Do Not Mix Injector Types

   When replacing injectors, do not mix genuine OEM and aftermarket parts due to differences in oil output and atomization concentration. It is highly recommended to replace the entire set of injectors to avoid potential imbalance issues.

5. 5

   Post-Repair Testing

   If leakage was severe, complete the fuel pressure test procedure immediately following the pump or injector replacement to ensure the repair was successful.