I just changed the glow plugs in my 99 E300, which required the removal of several parts, including the air intake, disconnected some fuel lines, removed two injector hard lines, etc., then put them all back once the glow plugs were changed. Once back together, I started the car and within 5-10 sec, the engine was running smoothly and sounded good. very normal. After 5 min. or so of idling, the engine stumbled a little, then died. I tried to restart, but it only felt like 2 of the 6 cylinders were trying to fire, but not enough to start. I removed the main fuel filter to discover it was only about 1/2 full. I check the pre-screen filter at the fuel filter housing and that was essentially dry. I filled a new filter with fuel, but it still would not start. So, where else do I go to diagnose the problem? Do I drain the tank and check the screen? I am running DSE diesel, which is a vege-oil blend. Any thoughts would be greatly appreciated. Thanks,

 

On the earlier models it is easy to disconnect the Fuel Inlet Hose and replace it with a longer hose (maybe you can find a way to do this with your mode.) that goes into lets say one of those 2.5 liter spare Fuel Containers; for testing fill it with regular Diesel Fuel.
Doing this bypasses the Fuel System to the rear and your Fuel Supply Pump does not have to pull the Fuel as far. If it starts and runs well on the Fuel Container that will give you an idea of where to look for an Air Leak.
Since your Fuel Supply System has no Hand Primer you have no choice but to crank the Engine to get the Fuel moving. Even though your Fuel Injection Pump is supposed to be self bleeding I would loosen the Fuel Injection Lines at the Injectors and crank until you see Fuel coming out from under the nuts and then tighten them before starting; as this could shorten the cranking time.
It is also nice to have either another Battery Available or a Battery Charger so as not to ruin your Battery.

Also if your Fuel Hoses seal with O-rings it is possible an O-ring got nicked or damaged and is not sealing.