Has anyone repaired an injector?

Hello friends, whether the 1.4 hdi injectors can be maintained or if they are damaged, it should be replaced completely. I think that there is no problem with the departure of my vehicle, but the light blue smoke in the morning means urination.

Hello, my teacher is repairing. It would cost an average of 500-1500 TL depending on the condition of the injectors. glow plugs will appear if the pc is defective when viewed.

Thank you