what have i done wrong??

You don't say whether it is running or not,but have noticed on Renault motors that there is usually signs of air in fuel piping when ticking over and think this is normal, no running faults with them at all, not sure on yours but when emptying the filter there may be a hand primer near the filter, if not it can be filled manually with clean diesel and this can save a lot of cranking, some motors are very difficult to get going again if you don't do this, your bad starting could be down to other issues like glow plugs and a code reader would usually pick up any faults associated with them or any other system faults that are logged, good luck.

cdc
April 2016