Thank you for reply.

I am trying to avoid taking the Injection Pump out. My local Indy wants over $1000 for taking the pump out and back in. Then I have to take it to Bosch, which will cost another $600-$800. Mercedes quotes replacing the pump for around $2000 with MB rebuild pump....

I spoke with a couple of MB indy who work on this pumps and they said there is a groove on the barrel where the pin should lock and according to them, it should do it. So, my first goal is to see if doing that fixes my issues, if not, I may get the MB to change the pump.