renault master van hard to start when cold?

hi i have a 2002 master van 2.2 dci when i leave the van all nite are for 2 hour its hard to start its like it not getting fuel its heating ok when i get it started and leave it runing it cuts out after about 5 mins but starts ok i think its losting pressure in the fuel line when i leave the van of the fuel is falling back in the line from the filter back about 4" in the fuel line does any one no what it could be or what part i need thanks