When reinstalling the fuel injectors one of them got damaged, see first pic below. The small plastic cap in the centre cracked when I applied the small amount of force needed to push the injector into the seat. All that was left of the cap was crumbles I removed the crumbles and what is instead seen is the end of a steel pipe. What is the purpose of this cap? Can I safely ignore the loss?

 

The last 5 injectors I drove into their seats using a custom socket made from a piece of a plastic paint brush handle. Worked fine with no damage done to the remaining injectors