Well that's very strange.
The tank pump is supplying diesel to the high pressure pump.
The high pressure pump is I think driven by a belt, with no need toi time it up, it is simply an engine driven pump
Yet with the pipes to the injectors cracked open there is no delivery to the injectors.
Is that right ?
If so, are you sure you have not got the supply and return pipes reversed (probably not even possible but I put it out there as an idea)
If my instructions were not clear, when you crack the injectors off, release all 4 and wait for one to start squirting, then tighten just that one.