I have a 2003 megane 1.9 DCI, big ass type. It has a probelm after an engine change (old engine had a bent rod) , The car will start straight away on the button everytime but after 3 seconds or so it dies. During that 3 seconds you can rev it freely etc as thopugh it were ruinning fine. Watching live data it doesnt seem to lose crank signal or fuel pressure, it just stops as though the ECU were requesting it. there are no fault codes etc coming up.The flywheel and sensors etc are all original to the car, timing is correct and there are no leaks or air in the fuel system.