Help needed please

[Craigyd82]

Hi all, I have a 2012 fiesta 1.4 tdci 70bhp, I've replaced the engine and I can't get it to start, it will only crank off the key for 1/2 seconds then cuts the starter off, it has fuel coming out of the return pipe when cranked but no fuel to injectors, it will fire with easy start then cuts out, I put the original injectors into new engine so shouldn't be a coding issue, could it be an immobiliser problem? Tia for any replies, it's annoying me now .