Gas Mileage Computer Accuracy

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Old 03 Mar 2004, 12:43 pm   #1 (permalink)
Lew
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Default Gas Mileage Computer Accuracy

Does anyone know how this works? Specifically does it use an actual
fuel flow measurement (which presumably is accurate) or some other
approach which would be less accurate. My 2004 Camry 4 shows about 29
mpg average but I get only 23. Dealer blames it on oxygenated gas and
dismisses the mileage readout as only a rough guess. Says its only
input is from the fuel tank sending unit but I don't see how that is
possible since it knows almost instantaneously when I am going up or
down a hill. Anybody have any experience with this issue.
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Old 03 Mar 2004, 01:40 pm   #2 (permalink)
Philip®
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Default Re: Gas Mileage Computer Accuracy

In news:a716740b.0403031043.73848e87@posting.google.c om,
Lew <lgaines100@yahoo.com> being of bellicose mind posted:
> Does anyone know how this works? Specifically does it use an actual
> fuel flow measurement (which presumably is accurate) or some other
> approach which would be less accurate. My 2004 Camry 4 shows about
> 29 mpg average but I get only 23. Dealer blames it on oxygenated
> gas and dismisses the mileage readout as only a rough guess. Says
> its only input is from the fuel tank sending unit but I don't see
> how that is possible since it knows almost instantaneously when I
> am going up or down a hill. Anybody have any experience with this
> issue.


Based on calculations from injector spray duration, manifold vacuum
(or air flow), idle time, vehicle speed, engine RPM, and fuel tank
level.

Oxygenated fuel does increase fuel consumption (lower MPG).
--

- Philip @ Maximum Torque RPM


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Old 03 Mar 2004, 08:50 pm   #3 (permalink)
Stevie Ray
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Default Re: Gas Mileage Computer Accuracy

In article <Swq1c.19840$aT1.1567@newsread1.news.pas.earthlink .net>,
Philip® <1chip-state1@earthlink.net.invalid> wrote:

> In news:a716740b.0403031043.73848e87@posting.google.c om,
> Lew <lgaines100@yahoo.com> being of bellicose mind posted:
> > Does anyone know how this works? Specifically does it use an actual
> > fuel flow measurement (which presumably is accurate) or some other
> > approach which would be less accurate. My 2004 Camry 4 shows about
> > 29 mpg average but I get only 23. Dealer blames it on oxygenated
> > gas and dismisses the mileage readout as only a rough guess. Says
> > its only input is from the fuel tank sending unit but I don't see
> > how that is possible since it knows almost instantaneously when I
> > am going up or down a hill. Anybody have any experience with this
> > issue.

>
> Based on calculations from injector spray duration, manifold vacuum
> (or air flow), idle time, vehicle speed, engine RPM, and fuel tank
> level.
>
> Oxygenated fuel does increase fuel consumption (lower MPG).
> --
>
> - Philip @ Maximum Torque RPM
>


My dealer advises that none of them are axurate on the Camrys. They
just represent an estimate and it can not be calibrated. SUCKS!
>

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Old 03 Mar 2004, 09:27 pm   #4 (permalink)
Philip®
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Default Re: Gas Mileage Computer Accuracy

In news:030320042050430907%stevieray@hotmail.com,
Stevie Ray <stevieray@hotmail.com> being of bellicose mind posted:
> In article <Swq1c.19840$aT1.1567@newsread1.news.pas.earthlink .net>,
> Philip® <1chip-state1@earthlink.net.invalid> wrote:
>
> > In news:a716740b.0403031043.73848e87@posting.google.c om,
> > Lew <lgaines100@yahoo.com> being of bellicose mind posted:
> > > Does anyone know how this works? Specifically does it use an
> > > actual fuel flow measurement (which presumably is accurate) or
> > > some other approach which would be less accurate. My 2004
> > > Camry 4 shows about 29 mpg average but I get only 23. Dealer
> > > blames it on oxygenated gas and dismisses the mileage readout
> > > as only a rough guess. Says its only input is from the fuel
> > > tank sending unit but I don't see how that is possible since
> > > it knows almost instantaneously when I am going up or down a
> > > hill. Anybody have any experience with this issue.

> >
> > Based on calculations from injector spray duration, manifold
> > vacuum (or air flow), idle time, vehicle speed, engine RPM, and
> > fuel tank level.
> >
> > Oxygenated fuel does increase fuel consumption (lower MPG).
> > --
> >
> > - Philip @ Maximum Torque RPM
> >

>
> My dealer advises that none of them are axurate on the Camrys.
> They just represent an estimate and it can not be calibrated.
> SUCKS!


Driving computers on other brands are no better. These driving
calculators provide ONLY an ESTIMATE. The estimate is usually on the
low side so that it will be less likely that you get stranded on the
side of the road with the display saying you've got 15 miles left.

I am becoming hardened to GADGET people who get their panties all
tied up in a knot over STUPID gadgets.

You bought a CAR.

You should dismiss all notions that you bought an electronic
amusement center on wheels.

Put a strip of black Duct Tape over the damned fool driving computer
until you can get yourself into a base model Camry ... a CAR that is
meant to move your butt from place to place in comfort.
--

- Philip @ Maximum Torque RPM


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Old 07 Mar 2004, 02:59 pm   #5 (permalink)
S & B
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Default Re: Gas Mileage Computer Accuracy

Lew <lgaines100@yahoo.com> wrote:

> Does anyone know how this works? Specifically does it use an actual
> fuel flow measurement (which presumably is accurate) or some other
> approach which would be less accurate. My 2004 Camry 4 shows about 29
> mpg average but I get only 23. Dealer blames it on oxygenated gas and
> dismisses the mileage readout as only a rough guess. Says its only
> input is from the fuel tank sending unit but I don't see how that is
> possible since it knows almost instantaneously when I am going up or
> down a hill. Anybody have any experience with this issue.


The mileage display on my 2003 4-cly XLE consistently reads about 22%
high.

The dealer essentially said that nothing can be done (or would) but
offered to have me meet a higher level guy that comes to the dealership
once or twice a month. So far, every time the guy was there, I had other
committments. But, maybe one of the days!!

Otherwise the car is great.
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