Case IH 19913 – Engine Control Unit (ECU): Error in comparing energizing time to minimum value for injector in cylinder 1

The engine management system routinely performs a Zero Fuel Calibration (ZFL) while the engine is at low idle. The ZFL evaluates and learns calibration values to adjust the energizing time (pulse width) of the pilot fuel injection. If the ECU detects that the energizing time required for the cylinder 1 injector has dropped below the minimum allowable programmed threshold, it logs this code. This typically indicates that the injector is worn, leaking, or mechanically delivering too much fuel, forcing the computer to try and shorten the injection time beyond its minimum limit to maintain a smooth idle.

• Tier 4b
• Case N-Series Loader Backhoes (Tier 4 Final)
• Case IH Farmall compact tractors (e.g., Farmall 35C, 40C, 50C, 50B)

1. 1

   Inspect the wiring harness and connectors leading to the cylinder 1 fuel injector for shorts to ground or resistance issues that could alter the solenoid's electrical characteristics.

2. 2

   Perform a return flow (leak-off) test to see if the cylinder 1 injector is bypassing excessive fuel compared to the other cylinders.

3. 3

   Use the Case IH Electronic Service Tool (EST) to perform a cylinder contribution test to verify the performance of cylinder 1 at idle.

4. 4

   Verify that the fuel rail pressure is within specification at low idle, as abnormal pressure can skew ZFL calibration times.

1. 1

   Preparation

   Disconnect the battery. Remove any engine cowlings or components necessary to access the fuel rail and injectors.

2. 2

   Disconnect Lines

   Disconnect the electrical connector from the cylinder 1 fuel injector. Carefully loosen and remove the high-pressure fuel line connecting the fuel rail to the cylinder 1 injector. Cap the rail fitting and the line immediately to prevent contamination.

3. 3

   Remove Injector

   Remove the injector hold-down clamp/bolt. Carefully extract the cylinder 1 fuel injector from the cylinder head.

4. 4

   Clean the Bore

   Clean the injector bore in the cylinder head thoroughly. Ensure the old copper sealing washer is removed and not stuck at the bottom of the bore.

5. 5

   Install New Injector

   Install the new fuel injector equipped with a new copper sealing washer and O-rings.

6. 6

   Reassembly

   Reinstall the hold-down clamp and torque to OEM specifications. Reconnect the high-pressure fuel line and torque to spec. Reconnect the electrical connector.

7. 7

   System Bleed

   Reconnect the battery and prime/bleed the fuel system.

8. 8

   ECU Programming

   Connect the Electronic Service Tool (EST). You must program the new injector's trim code (IQA/QR code printed on the new injector) into the ECU.

9. 9

   Calibration

   Start the engine and allow it to reach operating temperature so the ECU can perform a new Zero Fuel Calibration (ZFL) at low idle. Clear the inactive fault codes.