Iveco 277 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Poor combustion of the fuel-air mixture in cylinder 3

The engine control system has detected that cylinder 3 is underperforming or misfiring, failing to contribute the expected power during its combustion stroke. This is typically caused by a faulty fuel injector, a loss of cylinder compression, or air trapped in the fuel lines.

• Iveco Stralis
• Iveco Eurocargo
• Iveco Tector
• Iveco Daily

1. 1

   Check for air in the fuel system and bleed via the bleeder screw on the fuel filter housing.

2. 2

   Inspect the wiring harness and connectors leading to the cylinder 3 injector for chafing, oil intrusion, or loose connections.

3. 3

   Use a diagnostic scan tool to run a cylinder balance/contribution test to verify that cylinder 3 is the isolated point of failure.

4. 4

   Check the mechanical compression of cylinder 3 to rule out internal engine damage (e.g., worn piston rings, burnt valves, or a blown head gasket).

5. 5

   Verify that the low-pressure feed pump and high-pressure common rail are delivering fuel within specification.

1. 1

   Preparation

   Set the vehicle/machine in a safe condition and disconnect the battery cables.

2. 2

   Access the Injectors

   Disconnect the oil vapor pipes and remove the engine valve cover (tappet cover).

3. 3

   Disconnect Wiring & Lines

   Disconnect the engine wiring harness from the injector connectors. Disconnect the high-pressure fuel pipes from the common rail and the injector fuel manifolds. Note: Use a suitable backup wrench to hinder the flow limiter from rotating when loosening the rail connections.

4. 4

   Remove the Injector

   Remove the injector fastening screws or retaining clamp. Use the specified OEM injector puller tool (e.g., Tool #99342101 for Tector engines, or Tool #99390804 for Cursor engines) to extract the injector from the cylinder head.

5. 5

   Clean the Bore

   Use a deposit removal tool (e.g., Tool #99390772) to clean the injector holding case/cup in the cylinder head.

6. 6

   Installation

   Install the new injector with new O-rings and copper sealing washers. Reinstall the retaining clamp and torque the fastening screws to OEM specifications.

7. 7

   Reassembly

   Reconnect the high-pressure fuel lines and the electrical connectors. Reinstall the valve cover and reconnect the battery.

8. 8

   Bleed the System

   Attach a tube to the fuel bleeder screw, route it to a container, and loosen the screw. Run the priming pump or idle the engine for a few minutes until all air is purged from the system. Tighten the bleeder screw securely to prevent fire hazards.