On Thursday, July 20, 2017 at 10:02:01 PM UTC-4, Mad Roger wrote:
On Thu, 20 Jul 2017 19:56:12 -0600,
rbowman wrote:

If mom and pop are not taking advantage of readily available data from
the on-board computer systems they are either driving a 1972 Old Cutlass
or they are not part of the conversation. This is 2017, not 1917 when
you measured the tank level with a stick.

What's the accuracy & repeatability of the dashboard reading you speak of?

As you must already know, the tach isn't all that accurate on today's cars.


What cars? Like Bowman said, 1911 model cars? All cars today
have crankshaft position sensors that count the revolutions
with 100% accuracy. They then display it typically on an LCD
display that has enough resolution to be highly accurate.


The temperate gauge isn't accurate on current cars either.

The typical temp gauge doesn't display it with high accuracy,
if at all, but the onboard computer knows it very accurately.


Neither is the speedometer (to a few percent).

Few percent isn't good enough?


Nor the fuel gauge.

Why would a purely informational dashboard mpg display be accurate?
Or repeatable?


Maybe it is - but there's no reason for it to be accurate to +/- 2% of the
indicated reading. Even the $360,000 EPA tool, as I recall, wasn't accurate
to any better than that.

And who claimed the MPG reading had to be accurate to better than that for
it to be useful, interesting, etc.?



What's the accuracy & repeatability of the dashboard reading you speak of?