Poor starting,engine misfire

[dave.llan]

Hi,i hope someone can help,my 1.4tdi has become very hard to start only possible if i press the accelarator right down,then it will fire,but will misfire untill i travel for a while then the fault will dissapear only to come back when i start from cold.
anybody got any ideas?

 

[Hudson]

Sounds like fuel starvation when cold. Could be you have a fuel line with an airleak? With a Tdi more than a petrol if you get any air in the lines you'll get a misfire which once the line has fully charged will go away but when you stop the fuel will be able to loose it's prime and air gets in. Flooring the throttle will make the engine work harder to get fuel so perhaps expalins why you need to put your foot to the floor.

Sorry I can't tell you how to diagnose or fix the issue other than have a really good look at the fuel line etc and see if any look wet or worn. Running the car and gving them a wiggle may get them to squirt or leak more clearly but hot engine + fuel.....not the best solution. Sadly if the hole or leak is very small no fuel will get out but air will get in so very hard to find. I had this on an old 306 which thankfully very easy to work on and found the issue quite quickly as one of the line had clearly been rubbing on metal bracket.

 

[MikeMarsUK]

The fuel filters can also suck in air sometimes (particuarly if the garage has not used an Audi filter).