New Holland ENG 3291 – Engine ECU (EDC7): Cylinder 1 Specific Errors - No Signal

The engine control system has detected an open circuit or a complete loss of electrical communication with the fuel injector located at Cylinder 1. When this circuit breaks, the system cannot actuate the injector, resulting in a misfire, rough running, and a disabled cylinder.

• T6 Series
• T6.120
• T6.175
• T7 Series
• T7.170
• T7.260
• T8 Series
• T8.275
• T8.435
• T6000
• T7000
• CR9090
• CX8080
• CX8090
• CR5.85
• TC5070
• B95B
• B100B
• B110B
• B115B
• LB90.B
• W190B
• D85B
• D95B

1. 1

   Visually inspect the wiring harness running from the EDC7 ECU to the Cylinder 1 injector for chafed wires, melted insulation, or disconnected plugs.

2. 2

   Disconnect the harness at the injector and at the EDC7 module to inspect the pins for corrosion, moisture ingress, or bent terminals.

3. 3

   Use a multimeter to test the continuity of the wiring between the ECU and the injector.

4. 4

   Measure the resistance (impedance) across the Cylinder 1 injector solenoid terminals to check for an internal open circuit in the injector.

5. 5

   Connect the Electronic Service Tool (EST) to read stored faults and run an injector diagnostic test (e.g., shut-off path test or positive test) to verify EDC7 power stages.

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent electrical shorts or accidental ECU damage.

2. 2

   Gain Access

   Remove the engine valve cover or necessary cowling to access the fuel injectors and the common rail system.

3. 3

   Disconnect Wiring

   Carefully unplug the electrical connector from the Cylinder 1 fuel injector.

4. 4

   Remove High-Pressure Lines

   Loosen the nuts and extract the high-pressure fuel manifold/lines connecting the common rail to the Cylinder 1 injector. OEM Caution: Once removed, these high-pressure fuel manifolds must NOT be reused; they must be replaced with new ones to prevent severe fuel leaks.

5. 5

   Extract Injector

   Remove the injector hold-down clamp/mounting hardware and carefully extract the faulty injector from the cylinder head.

6. 6

   Install New Injector

   Clean the injector bore. Install the new injector with a new sealing washer/O-ring and torque the mounting hardware to OEM specifications.

7. 7

   Install New Fuel Lines

   Install the brand-new high-pressure fuel line/manifold and torque the fittings to spec.

8. 8

   Reassemble

   Reconnect the injector electrical harness, reinstall the valve cover (using a new gasket if required), and reconnect the battery.

9. 9

   ECU Programming

   Connect the EST diagnostic tool. Clear the ENG 3291 fault code and, if required by the specific FPT engine generation, program the new injector's calibration code (IQA code) into the EDC7 ECU.