Renault Clio 2003 1.5 DCi Head Change Help

[jw_clio]

Hi all,

Im new to forums dont usually need them although always read up on them... Cant see a thread available for a problem i have so any suggestions are much appreciated...

Car: Renault Clio 1.5 DCi (uk '53' plate)

I had a problem with the injector on the old head unit so over this weekend i have changed the Head Unit on the car to a newer one with 4x newer injectors...

Everything went quite smoothly with removal and re-fitting however i now have a problem with the engine starting...

The engine turns over however makes no attempt to fire... fuel system seems good diesel goes through all 4 injectors and have some smoke from exhaust on turning over suggesting exhaust system is fine...

In the car no on dash lights suggesting a problem with computing etc only the engine light flashes when ive been trying to get it to fire for 30 seconds or so... (as i would expect anyway)

Any suggestions of where to look or anything i may have missed and need checking would be much appreciated????

Currently have the battery out as it ran flat with trying to get it to start and is on charge ready to have another go at it this evening after refuelling my stomach lol

Many thanks in advance as any help would be brilliant