"The sensors measure vibration of the fuel line"
Nope, not according to Diesel_John. I found his original post and he says he saw the whole pulse on a scope:
http://ecomodder.com/forum/showthrea...html#post34033
A lot easier to clamp a piezo on a line than to retrofit obdII if you happen to otherwise like your old diesel
. And even with obd you are not guaranteed fuel consumption feedback, I've heard a few reports about MPG on scangauges not working on diesels. So worth exploring a bit more anyway. Anyone want to donate an old vw diesel to me?