1.9dci rough idle

[bernard1971]

8000 miles since last service my megane has now developed a rough idle pluged in diagnostic no faults holds 800rpm give or take 30 rpm
I work for an insurance company in their bodyshop and 50% of the megane's i work on idle as mine is now but its not right
to try and cure the problem today i have given it a full service but no improvment
but noticed today that air bubbles are visable in the transparent fuel line traveling towards what i think is the high pressure pump
is this visable on other megane dci's....if you ppl could have a look at the line to the pump to see if bubbles are evident it would be much appreciated
thanks

[tintin.dra]

Hi, I am fairly new to this so any help would be much appreciated.
I have recently bought a 1.5 dci and it runs perfectly but sometimes on idle it is very rough and feels like it is really struggling to tick over. The car shakes and feels like it is going to stall but if you rev the engine it picks up fine and then usually idles fine again.
I have noticed quite a lot of big air bubbles in the fuel lines and also sometimes when you first start it in the mornings it can smell quite strong like diesel.
Did you manage to get yours sorted or does anyone else have any ideas
Thanks,
Tintin

[lee00069]

sounds like maybe u have a leak on the common rail. Next time try use the hand primer in the morning before you start and you will see if it is possibly getting air in or loosing pressure on the fuel line

[tomalamix]

its the same on cold or warm?

[davelowe]

I've seen bubbles in mine, yet it runs well. Alex, many years ago now, diagnosed this problem as a pin prick hole in the fuel line. The vacuum generated by the fuel pump introduces air, yet at the same time is so small as to not reveal a leak. I would check for areas where the fuel lines might chafe against the bodywork/other components.

The smell of diesel could mean many things: leaks; a rich mixture, EGR problems... Obviously, if you find a puddle under the car, you are halfway there.