I am wondering if there is a portable or a semi portable mileage computer available out there for diesel cars and or trucks!
In the Dodge diesel pickup the factory mileage computer is open-loop, in that it's not measuring fuel consumption at all. (This is difficult to do, especially with a fuel return line to measure also.) Instead it just measures the position of the fuel rack and consults its internal table of fuel delivery to _assume_ what is being consumed. Tolerably accurate, unless there is something wrong or modifications have been made. Certainly as accurate as, let us say, a temperature gauge that only has two positions!
I have always assumed that this is because measuring true consumption is difficult, expensive, or involves relatively unreliable sensors, or some combination of the above. I also assume that they pretty much all do it this way, so it's not like the junkyards are filled with easily-salvageable fuel flow sensors. -- Jim
