td4 wont start

hi guys am new on hear and in search of help.... i own a td4 54 plate bmw engine....... started having problems , where it took a couple turns before it would start, after few daysd it died... would starrt on easy start and run perfect and would restart on its own if turned it off but longer you left it harder it would be to start and after hour or so would not start , then got worse and would not run at all..... swapped crank sensor!! cam sensor!! high pressure sensor on common rail...all with 2nd hand parts told working, but still no look, changed the high pressure fule pump today and car will fire up, but running very lumpy as if on 3 cylinders or running at veery low revs around 500rpm, wont rev and cuts out after about 10 seconds and wont fire again on turn of key unless you leave it for 5 mins..... car previously been on diagnostics and give severall codes all indicating fuel pressue...... also previously leak off test drew a blank as none of the bottles filled up!! anyone any ideas... oh the rear fuel pump is working too and checked the pick unit in the tank all ok????? am stumped hellp

Have you checked your battery . Sounds like its knackered .








And search ffs .

def not the battery, when car running for the few seconds its running it wont rev