Strange 'Range' Behavior

[Huw Powell]

You filled with cold gas, then drove out of the city onto the highway.

As the gas warmed up it expanded, raising the fuel level float, at the 
same time as your average fuel economy was going up.

Personally I don't trust any of those on-board reports to be 
particularly accurate.

- Huw

On 9/12/2014 1:16 PM, Dan DiBiase wrote:
> That's what I thought, until it stayed on 235 miles for 20 minutes.....
> Couldn't rationalize that....
>
> Dan D
> '04 A4 1.8Tq MT-6
> Central NJ USA
>
> ------------------------------------------------------------------------
> *From:* Cody Forbes <cody at 5000tq.com>
> *To:* "audi at humanspeakers.com" <audi at humanspeakers.com>
> *Cc:* "quattro at audifans.com" <quattro at audifans.com>
> *Sent:* Thursday, September 11, 2014 7:34 PM
> *Subject:* Re: Strange 'Range' Behavior
>
> I think it uses an average MPG from an unknown degree of history (not
> indefinite, maybe 100 miles?). Once on the highway and cruising it
> shouldn't fluctuate much, but getting off the highway for the pit stop
> would throw the average off.
>
> -Cody Forbes (mobile)
>
> On Sep 11, 2014, at 7:03 PM, Huw Powell <audi at humanspeakers.com
> <mailto:audi at humanspeakers.com>> wrote:
>
>  > Copying for the OP
>  >
>  > On 9/11/2014 8:46 AM, Dan DiBiase wrote:
>  >> Took my A4 on it's first road trip in a while, from Central NJ to
> Saratoga Springs, NY and back. A function of our new car having satellite
>  >> radio, I guess...! Anyway, was surprised at the fuel mileage -
> averaged 35 mpg each way - granted, it's 99% highway miles, and traffic
>  >> was light so the cruise was set at 72 mph and hardly had to touch
> it. That is higher mileage than I have gotten in the past, by a couple
> of mpg's.
>  >>
>  >> The strange thing was the range computation. Going up, I used just
> under half a tank of gas so I was monitoring the range closely to see how
>  >> far I could get before I needed to stop to ensure I didn't roll into
> the driveway on fumes - second half of the tank always seems to go faster
>  >> than the first.... ;-) When I got onto the highway, the range
> actually went up about 10 miles, which I assumed was due to the better
> gas mileage
>  >> I was getting than in the little bit of stop-and-go traffic
> approaching the Northway. It kept going up for a while, then starting
> going down, but at
>  >> a very uneven rate, and finally sat on 235 miles for a good 20
> minutes (during which time I would have driven about 24 miles). So I
> ended up
>  >> pulling off and putting some gas in but didn't reset the computer.
> Got back on the highway and the range read 440 miles, then proceeded to
>  >> drop about 5 miles for every 2 miles driven until it seemed to be at
> a 'normal' level for the fuel I had remaining in the tank - then went down
>  >> normally at that point.
>  >>
>  >>
>  >> I always assumed that the range calc was a simple 'look at the fuel
> level, look at the mph and compute' sort of thing and don't recall it ever
>  >> fluctuating so much.
>  >>
>  >> Anyway, it was nice to get reconnected with the car, since it
> doesn't get much use now that my daughter has gone to college and her Mini
>  >> Cooper is sitting there calling for me to drive it.... But I wish it
> had satellite radio....
>  >>
>  >>
>  >> Dan D
>  >> '04 A4 1.8Tq MT-6
>  >> Central NJ USA
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