If the van has been sitting for a while it could be that gum has developed in
the injectors and injector pump.  This can make a diesel VW a bear to start.
We use this injector cleaner called "Fireball" to clean the system out.  The
best way I have found to do this is to unhook the fuel line to the injector
pump.  Mix some fuel with the injector cleaner and put it in a plastic oil
bottle.  Get one of those pointed caps that go on gear oil containers and
screw it onto the oil bottle.  Now get a short piece of fuel line and connect
it between the oil bottle and the injector pump.  When you attempt to crank
the van over get someone to squeeze the bottle.  This clears out the gunk the
fastest.  You can just put some cleaner in the tank and let it work its way
through the system but this takes a long time to get to the pump.
Also hard starting can result from air leaking into the fuel lines and letting
the fuel drain back into the tank.  Check those short hoses in between the
injectors and if they look suspicious change them.  Also check out the two
rubber plugs on number 1 and 4 injector.
Have fun with your diesel and try not to chirp the tires every time you leave
McDonalds :)
Ken Wilford
Van-Again
John 3:16