I just bought a ’90 9000 CD Turbo, and the trip computer mileage indicator
drives me a little bit crazy. I can understand how it goes below 20 miles an
hour when you are accelerating, what I don’t understand is why it goes up to
80 or 90 when you take your foot off of the accelerator. Is this supposed to
be happening.
SFreund
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If you are talking about the horizontal led display that moves as you
press the gas pedal and take your foot off, it is normal. The horizontal
displays fluctuates with the vaccum as you accelerate and decelerate.
The number you should be concerned with it your actual mileage in the
display window. My 87 9000S averages 31 to 34 on the highway and 29 mpg
around town. I expect that to increase. I just put in a set of the Bosch
Platinum +4 plugs. My friends 87 9000T increased from 350 miles per tank
for local driving to 380 miles per tank. His foot is heavier than mine.
Ken Washington
87 9000S
87 900S
83 900T
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Comment by admin — February 10, 2010 @ 3:59 am
<sfre…@my-dejanews.com> wrote:
> I just bought a ’90 9000 CD Turbo, and the trip computer mileage indicator
> drives me a little bit crazy. I can understand how it goes below 20 miles
an
> hour when you are accelerating, what I don’t understand is why it goes up
to
> 80 or 90 when you take your foot off of the accelerator. Is this supposed
to
> be happening.
Of the two 9000s I have owned and 4 other 9000s I have driven (all pre-’90′s
FWIW), the "trip" computer has indicated two different MPG readings:
average and instantaneous. You can press the "INFO" button to cycle through
these settings, as well as estimated range in miles, voltmeter, and outside
temperature.
You are almost definitely looking at the instantaneous reading, and, yes, it
is known to fluctuate this much. The instantaneous MPG changes based on
both your vehicle’s speed and engine speed, and can, under certain
conditions indicate what would seem in the long term to be either a
ridiculously high or low value.
To reset the average MPG, hold down the "R" and "INFO" buttons for about 5
seconds. I have noticed that the average MPG reading tends to err a tad on
the conservative side. For example, my ’86 9000T generally estimates 24-26
MPG but when I fill up at the pump and calculate mileage, it’s usually
between 26-30 MPG.
Your mileage may vary (literally!),
-Doug
Comment by admin — February 10, 2010 @ 3:59 am
> Is this supposed to
>be happening.
Yes – it is giving you your current mileage within a second or so – NOT your
average mileage. Think about it — in order to average 30 MPG – if you
sometimes drop to 20 or 10 MPG or less under hard loads, you must at other
times be operating at 40 or 50 MPG or more for it to average out, and YOU ARE
if you are coasting. or coasting downhill with the wind behind you, etc.
Alex
Kuel is as Kuel duz!
Comment by admin — February 10, 2010 @ 3:59 am
In article <7g7vm9$ui…@nnrp1.dejanews.com>, sfre…@my-dejanews.com
wrote:
>Subject: trip computer
>I just bought a ’90 9000 CD Turbo, and the trip computer mileage indicator
>drives me a little bit crazy. I can understand how it goes below 20 miles an
>hour when you are accelerating, what I don’t understand is why it goes up to
>80 or 90 when you take your foot off of the accelerator. Is this supposed to
>be happening.
My understanding is that on the over-run (or coasting) (ie you are not
accelerating or even using the engine to maintain forward speed against
wind, rolling and other frictions) the fuel supply is cut off to the engine
so that in fact the car is (at that time) travelling at infinity miles to
the gallon.
So, if you could just arrange for all your trips to start at the top of a
hill, and finish at the bottom, you would use very little petrol. Physics
and the world being what they are, I find that every downslope on the
outward journey is matched by an upslope on the way home (or vice versa!)
and so I continue to use o non-infinitesimal amount of petrol. Pity!
Hugh Browton (’87 9000 SE T)
Comment by admin — February 10, 2010 @ 3:59 am