New Holland ENG 3303 – Engine Control Unit (ECU) / EDC: Cylinder 4 Specific Errors - No Signal

The engine control module is not detecting an electrical signal or continuity from the fuel injector solenoid on cylinder 4. The underlying condition is typically an open circuit, a disconnected or corroded injector plug, a broken wire in the engine harness, or a completely failed injector solenoid.

• T8.275
• T8.300
• T8.330
• T8.360
• T8.390
• T8.410
• T8.435
• T9 Series
• T6000 Series
• CR6.80
• CR7.90
• CR8.90
• CR9.90

1. 1

   Visual Inspection: Inspect the electrical connector at the cylinder 4 fuel injector. Look for loose connections, pushed-back pins, or corrosion.

2. 2

   Harness Continuity Test: Trace the wiring harness from the cylinder 4 injector back to the Engine ECU. Check for chafing, melted insulation, or breaks in the wire (a common issue on heavy equipment exposed to vibration and heat).

3. 3

   Injector Resistance Test: Disconnect the injector and use a multimeter to measure the resistance across the injector solenoid pins. According to common rail diagnostic guidelines, a healthy injector should read very low resistance (typically around 0.57 ohms). An "OL" (open loop) reading confirms the injector solenoid has failed internally.

4. 4

   Actuation Test: Use an Electronic Service Tool (EST) or a manual injector pulse tool to command the cylinder 4 injector. Listen for an audible "click." If the wiring is intact but the injector does not click, the injector is faulty.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and thoroughly clean the valve cover and fuel rail area around cylinder 4 to prevent dirt from entering the engine.

2. 2

   Harness Repair (If Applicable)

   If the diagnostic tests revealed a broken wire, splice in a new injector connector pigtail or replace the damaged section of the EDC7 wiring harness.

3. 3

   Remove Fuel Lines

   If the injector itself is faulty, loosen and remove the high-pressure fuel line connecting the common rail to the cylinder 4 injector. Cap the rail fitting immediately to prevent contamination.

4. 4

   Remove the Injector

   Remove the injector hold-down clamp/bolt. Carefully pull the injector out of the cylinder head.

5. 5

   Clean the Bore

   Clean the injector bore in the cylinder head, ensuring no old copper washers or carbon debris are left behind.

6. 6

   Install New Injector

   Seat the new injector into the bore. Crucial: You must use a new copper sealing washer and new O-rings.

7. 7

   Torque Components

   Reinstall the hold-down clamp and torque the bolt to the OEM specification.

8. 8

   Reinstall Fuel Line

   Install the high-pressure fuel line. (OEMs generally recommend replacing the high-pressure line once it has been removed, as the crush fittings are single-use). Torque the line fittings to spec.

9. 9

   Reconnect

   Plug the electrical connector back into the injector.

10. 10

    Finalize

    Reconnect the battery. Prime the fuel system to remove air. Start the engine, check for fuel leaks, and use a diagnostic tool to clear the ENG 3303 fault code.