Struggling to start after leaving overnight

[L33]

Renault megane mk one 1.9DTI
I have an issue with starting when left over night it doesn’t make a difference if it’s warm outside.
it cranks for ages then eventually fires with a puff of white smoke followed by a rough idle for about 20 seconds. If then left for about 4 hours you only have to show it the key and away it goes with no problems. Has anyone have any advice for me please.

[L33]

Just wanted to add I left the car overnight and it’s fairly warm outside today I went to start it and it was ok with just a slight rough idle.
This looks like it’s heat related I have already checked the glow plug circuit and all tested ok could it still be the glow plugs even though I have cleaned them and tested them on a 12v battery.

[Huskyxantia]

Check fuel lines aint letting any air in the sytem .

[Sloppysod]

Easily disturbed connections are those to the fuel filter.
Just a question, do you park with the bonnet facing up or down a slope, facing up a slope will exacerbate the problem.

[Sparlings]

Renault megane mk one 1.9DTI
I have an issue with starting when left over night it doesn’t make a difference if it’s warm outside.
it cranks for ages then eventually fires with a puff of white smoke followed by a rough idle for about 20 seconds. If then left for about 4 hours you only have to show it the key and away it goes with no problems. Has anyone have any advice for me please.

Did you ever get the bottom of this problem? Sort of had something similar recently.

[Muir]

It can be tricky to diagnose without Diagbox or similar tool to check things like fuel rail pressure while cranking.
My guess would be a fuel issue like Sloppysod pointed out - if the ECU does not see the minimum required fuel pressure on the sensor fitted in the common rail, it simply won't fire injectors.

Would suggest you trace the fuel lines for leaks from the tank all the way to each injector, even a small leak on the high pressure side can cause this issue.
If pipes and unions are already dirty/oily spray them down with brake cleaner, then take a drive till engine is heated up and recheck if you can spot any leaks.

[Dormouse]

Try switching on the ignition 2 or 3 times for about 6 - 10 secs and then go to start. This would prime the fuel lines by running the electric fuel pump (if fitted ) a few times before actually starting. You would still need to find out why the fuel pressure/supply drops just in case it is draining into the engine somehow.