A new or repaired injector is simply not enough. The problems during removal be faced with such during installation. In the video below you can perhaps recognize it. At the first cylinder escapes a sort of fog.

Accidentally the return lines directly at the injectors were not pushed in correctly. They dissolved and then diesel leaks during the test drive. Incidentally, the motor control has noticed it and the MIL lamp lit up. Blessing in disguise, you see when an injector is leaking.

As a remedial action, first the individual return lines were properly mounted on the injectors and then cleaned their surroundings. Of course, one may not dismantle an injector, surrounded by diesel fuel, because the fuel flowing into the combustion chamber is incompressible and therefore dangerous for the engine.

Very useful is the above visible cleaning kit for about 70 euros. You can close the last drilling towards the combustion chamber with a small piston with flange, O-ring and thread and open again after even rough handling with rotating wire brush and cleaning. One can even process the seat of the sealing ring with adhesive sandpaper of various grain size, by hand or with a drilling machine.

Please remember, the injectors necessarily (only) to tighten with the correct torque. We've overdone it. Although the construction has survived the test drive, but finally the M6 screw is tore off. Now we watch very closely: 8 Nm + 180° (even if this is difficult for some torque wrench). 06/16