Interesting questions. Where did you get the 300 PSI figure?
I am not the expert on this subject. Sometimes I surf the vwdiesel.net site to try and learn new things. Our same basic engine had a much larger and longer production run in the VWs so there is a naturally larger population of gearheads there and a more extensive knowledge base.
This fairly recent post caught my attention:
Gov mod AND timing mod??
Which lead to this one:
internal injection pump pressure
Quite a lot of info there, and not always so cut and dried. It will take some time to study all that info and arrive at a clear testing method but the results could be worth it.
My current thinking is that the first test to perform is the outflow test which seems to not require specialized equipment.
Your questions could probably be better answered if you posted them in the
Gov mod AND timing mod?? thread. Some of those recent contributors were also active in the older, more extensive
internal injection pump pressure thread.
Please report back and tell us what you find!