You are correct on the injectors, they are standyne pencil injectors that had many applications. I have found that you have to have at least some fuel going through injectors to make it bust on either. It sounds like you have a inj pump problem or a fuel problem. Lack of compression would not keep fuel from reaching the injectors. I am assuming that you have a mechanical fuel pump and if so the shaft in the pump is likely sheared. Aside from that be sure and check all the metal lines esp on the suction side, there are rubber grommets under the nuts that deteriate over time.