I just replaced the high pressure oil pump on my 2003 ford e350 deisel. Now it won't start. I did refill the reservoir with oil. It does crank, however it does not start. Any thoughts in this matter would be greatly appreaciated.

Well, the rule of all mechanics is it's either not getting fire or it's not getting fuel. I am sure that you know this already since you replaced the hp oil pump yourself. I would start by checking to see if your glow plugs are producing fire. I can't exactly remember how to do this, but I do remember that it's not very hard. One old school option is to take the ignition wire off and set it next to an area where it can ground (while the someone is trying to start the truck). I promise it's not dangerous. If you get spark, then it's good. Be careful though... even though this worked with older model vehicles, it might not be a good idea with newer models.

On to fuel pressure/fuel line problems. Make sure when you first turn the key that you can hear your fuel pump kick in. It's a unmistakable sound and generally happens when you turn the key to the point that you're ready to start. If your fuel pump seems to be working, you may need to get a pressure test. If you Ford is equipped with a fuel pressure gauge this will not be necessary.

The VERY FIRST thing you should probably check is good, stable connection from your batteries to the starter or solenoid and to the grounding areas (negative post, frame, alternator, or where ever it may be connected). If these are good, you might want to take a voltage meter and make sure you are getting good readings at the starter, solenoid, or grounding area... you could have a bad cable which will also cause this.