[Engine] [Now solved] 1.6 Hdi 'Missfire' under load (and a clonk)

[GraemeT]

OK - now we have the dreaded 'no start after injector change' scenario.

As previously stated - swapped out the 'wrong' 90HP injectors for a near set of scrapyard 110HP ones, recoded ECU and off we went. Next day no fuel pressure and no start (primer bulb very soft) - decided to leave it until full set of recon injectors arrived. They have and they're fitted/coded in.

Still nowt - tried a few things including pumping the hell out of that primer bulb but no joy. I have a feeling that you can't tow this one as there's a weird setup to the ignition so I think we've got an air lock in the system.

Googling has suggested priming the filter/low pressure side by a vacuum pump (which I happen to have) on the return line.
Also a possibility of cracking the high pressure feed pipes whilst cranking to get any air out of the system.

Any other suggestions that may/are known to work?