I've never needed a special wrench to take the injection lines off. Some some creative wrench placement and equally as creative swear words

To the OP, at least put that 4th bolt in there. It is essential, as your engine is proving.
why would you leave out such an easy to get to bolt? its literally just right there... and half the time you only need one wrench to loosen it because the tapered nut stays put. (most of the time)