To get a good analysis on the engine you should get the engine to exact factory specifications first - like the tappet gaps, the pump timing, the injector break pressure etc.
Once that is done you then check for loss of compression and oil pressure to determine if the engine is bad.
If your diesel is not in correct state of tune (bad timing, bad tappets etc) your engine will consume oil, be hard to start, have high volume blowby and be quite weak to run and sound bad too.