Edit: App has not been updated for years. I just used it on my 99.5 7.3 from the Android side of my chromebook and my Android10 phone, it worked fine. I'm using the OBDLink LX bluetooth adapter.
CarGuage Pro blutooth app is very powerful, cheap, but not intuitive. It will support some diesel features like the buzz test also. There are a couple of YouTube videos that will help out.