Weird startup problem :/

[Mike]

Hi all, my diesel is very sluggish to start, an if i dont hold the key in long enough it cuts out.
Then when i try an start it again it just turns over an wont fire at all.
Its a 95 dturbo on a lucas pump, the primer is workin fine, from the fuel lines etc ive checked around the pump, i cant seem to see any splits in the pipes, im clueless :/
I think ive narrowed it down to either the keypad immobiliser or somethings wrong with the fueling.
Ive tried to sort it myself but am stuck on what todo.
Anyone have any ideas of what todo?
Thanks
Mike