E39 530d not starting

[Galen]

Hopefully getting it plugged in today and see what comes up.

I'll check the pump after work, thanks

[318is-joe]

Sounds like an injector rail pressure drop (worse when hot) get a leak down test done on the injectors, or crank it with the leak pipes of the injectors, and see if one is pissing diesel, (short burst of starter)
If they aren't all within 10% of each other it will give the symptoms you describe - ideally you'd have manometers (graduated tubes) to connect with bosch connections to the injector tops.
Any half decent mechanic should be able to do this or if your handy yourself.....