Ok I am assuming you have a OM606.962 which was fitted to the 1998 and 1999 E300 Turbo Diesels.
edit:
Reason I ask is there is also a OM606.910 which was used on the 1995 E300 but it was a mechanical pump.
And a OM606.912 which has the electronic pump on the 1996 and 1997 E300 Non-Turbo Diesels.
I am further assuming you have a crank no start or dies while running condition.
The .912 and 962 injection pumps are electronically controlled by the ECU.
The fuel solenoid is also controlled by the ECU.
I had a problem with my 1998 E300 where it would die or fail to start. It turned out to be the crank angle sensor down on the left side of the bell housing.
Read my thread on this:
W210 CAN bus issues
Skip ahead to post #19 where I finally figure out the root cause.
It is very important to go to the dealer and get an MB branded sensor. For some reason the Bosch 'equivalent' will not work.