ODBII Program Car for better gas milage

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BennyB - 05 Oct 2006 19:50 GMT

Is it posible to change/program the car thru the OBDII to improve gas
milage? I saw this package of software to monitor and program thru the
OBDII at http://obdiitools.gdatabase.com/ . Has anyone used something
like this to improve/change gas milage or other performace.

Thanks,

BennyB

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Ray O - 05 Oct 2006 20:26 GMT

> Is it posible to change/program the car thru the OBDII to improve gas
> milage? I saw this package of software to monitor and program thru the
[quoted text clipped - 4 lines]
>
> BennyB

It is theoretically possible to flash the ECM through the OBD II system to
improve fuel mileage, but there are some things to keep in mind:

1) You will not have any warranty coverage on the ECM, including emissions
performance warranty.
2) You will not have any warranty coverage on any parts that are affected by
any reprogramming. For example, if a lean-misfire damages a part, there
will be no warranty coverage.
3) There is no inexpensive easy way to return the ECM to its original
programming if you are not satisfied with the results, like if the engine
runs poorly, or has so little power that it becomes undrivable.
4) Any improvement in fuel mileage will result in reduced performance and/or
engine and component life.
5) The folks who originally programmed the ECM are pretty knowledgeable
about the vehicles they designed, and so there is a pretty good likelihood
that given the overall design of the vehicle and taking into account the
vehicle weight, transmission, differential, and engine operating
characteristics, they have balanced fuel economy, engine performance, and
component longevity in their programming.
6) There is a good chance that an ECM that has been re-programmed by a
do-it-yourselfer will not comply with emissions requirements, so the vehicle
will probably not pass the state OBD II emissions test.
7) Fuel has different characteristics in different parts of the country and
during different parts of the year. The vehicle is programmed to take this
into account, and any new programming should also take this into account.
8) If the vehicle has an automatic transmission, reprogramming the
transmission ECM may also have to take place because of engine operating
characteristics.
9) The re-programming may make traction control and electronic stability
control malfunction.

Other than these few issues, there is nothing to stop someone with a
thorough understanding of how every component and sensor is controlled by
the ECM and the effect of variable signals from those sensors on
stoichometric efficiency couldn't go and do and re-program the ECM.

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Ray O
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MO full name - 05 Oct 2006 21:20 GMT

snip

>Other than these few issues, there is nothing to stop someone with a
>thorough understanding of how every component and sensor is controlled by
>the ECM and the effect of variable signals from those sensors on
>stoichometric efficiency couldn't go and do and re-program the ECM.

stoichometric = not a word - or perhaps a buzzword only.
Exactly what do you have in mind? There are people out there that
know a thing or two about chemistry <grin>.

http://www.websters-online-dictionary.org/definition/stoichiometry

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Mike Harris - 05 Oct 2006 21:35 GMT

> snip
>>Other than these few issues, there is nothing to stop someone with a
[quoted text clipped - 7 lines]
>
> http://www.websters-online-dictionary.org/definition/stoichiometry

...in automotive applications used to describe complete combustion of the
air-fuel mixture:

http://www.sae.org/technical/standards/J1829_200210

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Ray O - 05 Oct 2006 22:52 GMT

> snip
>>Other than these few issues, there is nothing to stop someone with a
[quoted text clipped - 7 lines]
>
> http://www.websters-online-dictionary.org/definition/stoichiometry

OK, my bad typing... the word should have been "stoichiometric", not
"stoichometric".

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Ray O
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Joe Schmuckatelli - 06 Oct 2006 00:51 GMT

>3) There is no inexpensive easy way to return the ECM to its original
>programming if you are not satisfied with the results, like if the engine
>runs poorly, or has so little power that it becomes undrivable.

Does this program not have a means to back up the existing settings so
that they can be restored?

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Ray O - 06 Oct 2006 01:21 GMT

>>3) There is no inexpensive easy way to return the ECM to its original
>>programming if you are not satisfied with the results, like if the engine
>>runs poorly, or has so little power that it becomes undrivable.
>
> Does this program not have a means to back up the existing settings so
> that they can be restored?

No, which is why I said that there is no inexpensive way to return the ECM
to its original programming.

The ECM is specifically designed so people cannot mess with the programming,
so it makes no sense to add a feature that adds cost and makes it less
tamper-proof.

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Ray O
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Joe Schmuckatelli - 06 Oct 2006 17:48 GMT

>The ECM is specifically designed so people cannot mess with the programming,
>so it makes no sense to add a feature that adds cost and makes it less
>tamper-proof.

The authors of this program have obviously gotten around that. If
they can alter the settings, I would imagine they can copy them off to
a configuration file for backup. Worst case scenario: write them
down by hand before making any changes.

Reminds me of a show I saw on TV somewhere. A team was designing and
building an updated Shelby Cobra. The body was together, and the
engine had arrived and was installed. Problem: the ECM needed to be
tweaked, and all the text displayed on the little monitor was in
Japanese... which nobody could understand. It took them all night to
get it straightened out.

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Ray O - 06 Oct 2006 18:27 GMT

>>The ECM is specifically designed so people cannot mess with the
>>programming,
[quoted text clipped - 5 lines]
> a configuration file for backup. Worst case scenario: write them
> down by hand before making any changes.

There are 2 pieces to the puzzle. The frirst piece is the ability to
re-program the ECM. The second piece is knowing how every component and
variable affects engine performance, fuel economy, emissions, and
drivability.
This is just a wild guess on my part, but I'd bet that there are a lot more
people who can hack the ECM and play with the program than there are people
who can actually make a useful improvement to the engine's performance.

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Ray O
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BennyB - 06 Oct 2006 21:40 GMT

I will have to check this software out some more to find out if it can
record the current setting before I start tweeking them. Any way,
thank you for all the input. Here is the link if anyone is interested
in the software http://obdiitools.gdatabase.com/

Later,

BennyB

> >>The ECM is specifically designed so people cannot mess with the
> >>programming,
[quoted text clipped - 13 lines]
> people who can hack the ECM and play with the program than there are people
> who can actually make a useful improvement to the engine's performance.

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Ray O - 06 Oct 2006 22:07 GMT

>I will have to check this software out some more to find out if it can
> record the current setting before I start tweeking them. Any way,
[quoted text clipped - 4 lines]
>
> BennyB

I'd be curious to see how the software works.

Since the ECM is programmed to answer if-then statements like

"If MAF voltage = A and throttle position = B and coolant temp = C and
intake air temp = D and brake light switch position = E and transmission
gear selector position = F and transmission gear position = G and the
position of the evaperative emissions purge valve is H and the signal from
sensor 1 bank 1 is I and the signal from sensor 1 bank 2 is J and the signal
from sensor 2 is K then injector # x pulse duration is L and ignition timing
advance is M, for all possible values of variables A thorugh K"

I imagine that it is not easy to come up with the solutions for L and M that
will make the car more efficient than the solutions that the factory
engineers came up with.

If you know how to solve that equation, then you have the knowledge to be
able to possibility make the car more efficient than the factory engineers
did. Otherwise, I think the results would be similar to what would happen
if I tried to make a Swiss watch more efficient.

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Ray O
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Andrew Stephenson - 06 Oct 2006 23:26 GMT

> [...] Otherwise, I think the results would be similar to what
> would happen if I tried to make a Swiss watch more efficient.

Hey, don't sell yourself short, Ray! You might get the watch to
sing "Cuckoo!" at 7 min 23 sec past the half hour. Or something
equally useful. ;-) (IOW -- for our slower readers -- I agree.)

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Andrew Stephenson

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Ray O - 07 Oct 2006 03:45 GMT

>> [...] Otherwise, I think the results would be similar to what
>> would happen if I tried to make a Swiss watch more efficient.
>
> Hey, don't sell yourself short, Ray! You might get the watch to
> sing "Cuckoo!" at 7 min 23 sec past the half hour. Or something
> equally useful. ;-) (IOW -- for our slower readers -- I agree.)

LOL! It would be interesting to see if anyone could actually get better
fuel mileage while preserving performance, and drivability without
increasing NOx, CO, and HC emissions.

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Ray O
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