I had this problem too the pipes turned out to be fine ,the fault was the tap valve in the ignition barrel that was not "delivering" enough vacume to the pump , a new one was £10 problem sorted .hope this helps
lee
October 2010
I have the same problem with this
Don Patterson
August 2010
the engine stops does work on a vacume, follow the thin black pipe from a small mushroom looking thingy on top of the fuel pump, the pipe goes to the ignition key, the key activates a tap to let vacume go down the pipe to the pump. check at what point you loose vacume.
Oly
February 2010
as you probably know the engine stop works via vacuum so you may have a leak in one of the pipes.
Ryan
February 2010
I can answer this question...
why will my mercedes sprinter 208 not turn off with the key?