Hi guys very new to fourm but not new to audis I hope some of you can help me get out of a tight spot.

Story goes..

Recently changed my engine over excuse of broken cam shafts and cracked the head..

Got a new engine and swapped all my parts from my engine over to the new one.

Replaced timing belt and gaskets etc,
The car had been off the road for over a year so put new diesel in and bled up the fuel system,

Right when turning it over it winds over for about 25 secs then goes to start, maybe starts for a couple of secs then dies again, then straight away will take another 25 secs to do the same, defo bled the air out of the system,
And double checked the timing the timing belt all locks up with pins in, and checked fuel pump timing, at tdc the fuel pump locking pin is at the top correct?

I do know it runs and idles if you keep spraying a little and I mean little of carb clean down intake but won't run off its own diesel!!

Also no codes on my scan tool.

I just was looking at advice before I think it's the fuel pump itself, anyone had similar issues,
I don't want to go down fuel pump issues as I belive before I bought the car the fuel pump had been replaced..

Many thanks steve