Honda Car Forum

Is there any way (formula) to calculate the fuel consumption (e.g.
L/100 KM or Gal/Mil) from values read from OBD-II interface?

I think next values could be taken into consideration to compute the
fuel consumption, but I don't know how exactly to interpret the result
of them:

Short Term Fuel Trim
Long Term Fuel Trim
Mass Air Flow
Fuel Pressure
Accelerator Pedal Position
Throttle Position
RPM

Chris

Chris wrote:
> Is there any way (formula) to calculate the fuel consumption?
I don't think it's possible, there are some programs that act like a
trim computer (showing instant MPG data, average fuel consumption,
etc.) but the actual fuel consumption will be different from what the
computer may show.
I just do this a simple way:
1. Note the reading of the fuel gauge when it's at easy to see exact
position (e.g exactly an 1/4 tank mark).
2. Reset the trip odometer to zero
3. Fill up the gas tank (it's easier if you fill up with even number of
gallons or liters, e.g 30 liters.
4. Drive and once the fuel gauge will show the position you noted when
you zeroed the odometer - check how many miles you drove.
So suppose you filled 30 liters and drove 250KM before the gauage shows
the same reading.
So you got 100x30/250=12L/100km

"Chris" <criro1999@gmail.com> wrote in news:1160064779.892720.143910
@i3g2000cwc.googlegroups.com:

> Is there any way (formula) to calculate the fuel consumption (e.g.
> L/100 KM or Gal/Mil) from values read from OBD-II interface?
>
> I think next values could be taken into consideration to compute the
> fuel consumption, but I don't know how exactly to interpret the result
> of them:
>
> Short Term Fuel Trim
> Long Term Fuel Trim
> Mass Air Flow
> Fuel Pressure
> Accelerator Pedal Position
> Throttle Position
> RPM
>



I seem to recall seeing a laptop-based OBD-II diag system that was capable
of the sort of number-crunching you need to do. I don't seem to have
recorded the maker, though.

Laptop solutions are software-based, with an adapter cable that conects the
OBD-II DLC port and a USB port on your laptop.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Here is a software for OBDII to do what you are talking about.
http://obdiitools.gdatabase.com/

I just do the old fashon way. When I pump gas I reset my milage or
write down the current milage and pump the tank full. That way next
time I pump I record that amount and divid it into the milage recorded
and get an average MPG.


Regards,


BennyB
TeGGeR® wrote:
> "Chris" <criro1999@gmail.com> wrote in news:1160064779.892720.143910
> @i3g2000cwc.googlegroups.com:
>
> > Is there any way (formula) to calculate the fuel consumption (e.g.
> > L/100 KM or Gal/Mil) from values read from OBD-II interface?
> >
> > I think next values could be taken into consideration to compute the
> > fuel consumption, but I don't know how exactly to interpret the result
> > of them:
> >
> > Short Term Fuel Trim
> > Long Term Fuel Trim
> > Mass Air Flow
> > Fuel Pressure
> > Accelerator Pedal Position
> > Throttle Position
> > RPM
> >
>
>
>
> I seem to recall seeing a laptop-based OBD-II diag system that was capable
> of the sort of number-crunching you need to do. I don't seem to have
> recorded the maker, though.
>
> Laptop solutions are software-based, with an adapter cable that conects the
> OBD-II DLC port and a USB port on your laptop.
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

On Thu, 5 Oct 2006 21:32:37 +0000 (UTC), "TeGGeR®" <tegger@tegger.c0m>
wrote:

>"Chris" <criro1999@gmail.com> wrote in news:1160064779.892720.143910
>@i3g2000cwc.googlegroups.com:
>
>> Is there any way (formula) to calculate the fuel consumption (e.g.
>> L/100 KM or Gal/Mil) from values read from OBD-II interface?
>>
>> I think next values could be taken into consideration to compute the
>> fuel consumption, but I don't know how exactly to interpret the result
>> of them:
>>
>> Short Term Fuel Trim
>> Long Term Fuel Trim
>> Mass Air Flow
>> Fuel Pressure
>> Accelerator Pedal Position
>> Throttle Position
>> RPM
>>
>
>
>
>I seem to recall seeing a laptop-based OBD-II diag system that was capable
>of the sort of number-crunching you need to do. I don't seem to have
>recorded the maker, though.
>
>Laptop solutions are software-based, with an adapter cable that conects the
>OBD-II DLC port and a USB port on your laptop.

Or you can buy one of these:

http://www.scangauge.com/

I bought the older and much clunkier first generation model. It works
very well and does all of above and more. ON caveat: fuel
consumption and related values (like miles to empty) are accurate only
to within 10% and perhaps more. Good for determining how speed
affects your fuel consumption but it doesn't replace actual fuel
consumption measurements made at the pump and I wouldn't use it to
decide whether I could make it to the next station.

gRmEcMgOrVeEw@mindspring.com (Gordon McGrew) wrote in
news:bl2ii29nl49dlkgvcge6staev03tg6ovio@4ax.com:

> On Thu, 5 Oct 2006 21:32:37 +0000 (UTC), "TeGGeR®" <tegger@tegger.c0m>
> wrote:
>

>>
>>Laptop solutions are software-based, with an adapter cable that
>>conects the OBD-II DLC port and a USB port on your laptop.
>
> Or you can buy one of these:
>
> http://www.scangauge.com/



I like these people already! Check out the photo on the home page.
129 mph! 5174rpm! Somebody's having some cheeky fun here!



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/