Injector pics-strange wear pattern?

[dweymer]

I pulled my injectors to do the orings, but they look "burnt" and the tips are very carboned. The burnt side faces the exhaust(down). Any ideas? Truck has 175k on it. I have had it since about 125k, unsure of the PO maintenance.

[Clay Henry]

Looks normal to me. Try water injection to keep that carbon cleaned out.