Some digital oscilloscopes have such soft.They are very useful because they help to identify difficult cases in the diagnosis of the mechanics of the engine, when the normal gauge or pneumotest useless or difficult to use.

It is possible to make adapters under glow plugs .In this case, the applied pressure transducers refrigerant from A/C MB :

If you have K9K , trouble code DF137 and that waveform in comparison with standart, one of the reasons - wrong pressure regulator.May be there is no correspondence between the control current, and a high pressure .Sometimes it may help flushing and blowing out with compressed air after removing pres...

PS. This sensor works like this:

PS.But if You have Simtec,it will be like that :

This old car dos not work without CRK sensor.Here it is CAM/CRK Picture for this Engine.Not in the best quality :