sprinter diesel running on

[fz911]

hi people, firstly i would just like to say hello to everyone
ive just bought a 97 mercedes sprinter 208d swb
im having a few problems with it,
first and foremost the engine wont shut off
second is the door locks dont seem to work
ive had a look thru a few problems from other members but none of these were specific sprinter problems
i have replaced the shut off valve on top of the fuel pump today (what a pain in the ...)
but still no improvement, i read on another post that the door locks run from the same vacuum system as the shut off pump on the back of the ignition switch,
do i have the same system on the sprinter, if i do then i think the problem will be solved, if i can find out where im losing the vacuum from,
any help would be appreciated
just to recap, my ignition switch is really stiff, hard to turn and stops on each click, the door locks turn a little but dont work so i cant lock it, and the engine wont shut down when i turn the ignition switch off
thanx carl