Case IH 19491 – Engine Control Unit (ECU): Fuel quantity Balancing Control correction quantities at limitation for injector in cylinder 3

The Engine Control Unit (ECU) has detected that cylinder 3 is either under-contributing or over-contributing to the engine's power output. The ECU has attempted to correct this by adding or subtracting fuel to cylinder 3, but the required correction has hit the maximum or minimum allowable limit programmed into the software, pointing to a physical issue with the injector, fuel delivery, or cylinder compression.

• Tier 4b
• Maxxum
• Puma
• Magnum
• Steiger
• Axial-Flow combines
• N-Series Tractor Loader Backhoes

1. 1

   Scan for related codes: Check the ECU for other fault codes indicating injector circuit shorts/opens, low fuel rail pressure, or crankshaft/camshaft sensor plausibility errors.

2. 2

   Perform a cylinder contribution test: Use a diagnostic tool to perform an electronic cylinder contribution test or an injector kill test to verify that cylinder 3 is the dead or underperforming cylinder.

3. 3

   Inspect wiring and connectors: Inspect the wiring harness and the electrical connector at the cylinder 3 injector for chafing, corrosion, or loose pins that could cause high resistance.

4. 4

   Perform a mechanical compression test: Perform a relative compression test via the diagnostic tool or a manual compression test to ensure the imbalance isn't caused by a mechanical failure in cylinder 3 (e.g., worn piston rings or leaking valves).

5. 5

   Check fuel quality: Inspect the fuel system for contamination, such as water in the fuel or debris, which commonly damages common-rail injectors.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical shorts and ensure safety.

2. 2

   Access fuel injectors

   Clean the area around the valve cover and remove the necessary engine covers to access the fuel injectors.

3. 3

   Disconnect electrical connector

   Disconnect the electrical connector for the cylinder 3 injector.

4. 4

   Remove high-pressure fuel line

   Loosen and remove the high-pressure fuel line connecting the fuel rail to the cylinder 3 injector. Cap the rail fitting immediately to prevent dust or debris from entering the fuel system.

5. 5

   Remove hold-down bracket

   Remove the injector hold-down bracket/clamp bolt.

6. 6

   Extract injector

   Carefully extract the injector from the cylinder head.

7. 7

   Clean injector bore

   Clean the injector bore in the cylinder head thoroughly, ensuring no old copper washers or carbon buildup remain.

8. 8

   Install new injector

   Install the new injector equipped with a new dust guard, O-rings, and a new copper sealing washer.

9. 9

   Reinstall hold-down bracket

   Reinstall the injector hold-down bracket and loosely tighten the bolt, then torque it to the specific OEM specification.

10. 10

    Install new high-pressure fuel line

    Install a new high-pressure fuel line (highly recommended for common rail systems) and torque the fittings to spec.

11. 11

    Reconnect electrical connector

    Reconnect the electrical connector to the injector.

12. 12

    Reassemble engine covers

    Reassemble the engine covers and reconnect the battery.

13. 13

    Program injector trim code

    Connect your diagnostic tool and program the new injector's trim code (IQA/IMA code, usually printed on the top of the injector) into the Engine ECU. This calibrates the ECU to the specific flow characteristics of the new injector.

14. 14

    Clear fault codes and test

    Clear the fault codes and test run the engine to verify the repair.