p38 brc lpg system advice needed......

Hi,
This is my first post and am hoping anyone can help.....
I have a 4.6 HSE P38 and recently had a friend do some engine work on it for me, the problem i have is that since then my gas system wont work properly, when i switch to gas it either stalls or cuts out.
Have had a look and as far as i can see there is the Genius max reducer with the gas and water pipes all connected correctly but there is a 10ml long pipe connected just below the electrical connector that is not connected to anything the other end, my friend who did the engine work seems to think its just some sort of breather pipe but im not so sure, could this be the reason why my gas wont work properly? and does anyone have any ideas as to where it should be connected to?
Thanks for looking.....
Liam.

Liam,

Mine is an L322 4.4 with BRC LPG. The 10mm pipe you are referring to (on my car) runs from the evaporator, along the centre of the V in the engine and is connected to a metal tube right at the back of the engine. It is close to the electronic control box but I dont think it connects to this box.

I have to stress that access is very difficult to this part of my engine and I have just been using it so it is very hot.

Certainly on mine, this is not a vent pipe, it could be vacuum or water.

Hope this helps.

PH