Coldfinger

Does changing the number change the air/fuel ratio?

MDXLT

It only manipulates the numbers for mpg to reflect a more accurate mpg number using 'the formula'. It's not a tuner.

However....

Did you know you can go into your online bank account and change the numbers to reflect a larger bank account?.....

msgtord

I do that everytime I spend to much on the truck. 😀

16IngotFX4

I was finally able to get into engineer mode a few days ago. Have not seen one written document explain how to do it the way my '16 works.

So for those of you that have done it, if you can remember, what percent off was it? As in, what is your new input value, approximately.

I made the adjustment after filling up a few days ago, haven't been able to confirm accuracy yet as I haven't burned up any fuel.

dougg

Lie-O-Meter...used a lot.

xrlizard

The first post on this thread explains the process, but the % off would vary from truck to truck I believe. On mine, the mileage read as 16.2 from the meter, but the actual calculated mileage was about 14.8-15.0. You divide the two, then multiply by 1000, and that gives the ratio to plug in. That gets you closer to the correct mileage reading on the meter. It is not an exact match, but gets you much closer.

16IngotFX4

I was apparently reading-comprehension challenged when I've read here before because I could swear I did exactly per post #1 but it never worked. reading it today when this thread became active again, that is exactly how it worked. LOL No bought it was operator error. No idea how I never figured it out from that first post, but it makes sense now that I know what to do. ha

As for the factor. I've already addressed it myself, but was actually curious if people remember what values they used. Just out of curiosity to see if there is an average 'error factor' if you will.
For example, mine seems to be off by 7% but I'm skeptical. It was off more this time than I've seen in past calculations. Generally an error factor of 3-4% (less than 1/2 mpg).

As for how to calculate, it's actually more easy than is described.

hand calculated/dash display
14.8/16.2=.913
Adjust the AFE Bias to 913. Saves a step of calculating the unnecessary 1000 factor.

xrlizard

@16IngotFX4 , glad you got it figured out. Yeah, I've thought about going back in and tweaking mine to be a little closer, but haven't gotten around to it yet. I think mine reads about .3 mpg better than it is actually getting, but it is still much closer than the original mileage.

16IngotFX4

Yep. One could adjust after every adjustment since we are humans and there is no way to make it exact. One time you put a splash more or less in the tank. Did you calculate out to 2 decimal places or 3. How close to rounding up was the pump when you shut it off today. All those things are minor but give a different rounding factor.

First time adjustment should be very close, send adjustment would be a minor percentage change.
I should go overbard and knock off another percent so that the dash displays poor economy, then when I calculate it out I'll be excited.

Honestly, I'll check the next couple fillups, then I will probably stop caring. I haven't calculated out MPG in 15 years. Mostly because I haven't had an accurate readout for um, 15 years. If the display is relatively accurate I'll stop caring and have it available for quick glance.

RLXXI

What blows my mind about this entire thread is why ANYONE that's concerned with MPG bought a truck.

Just fill the tank, do the job and be happy it performed as expected. Concerned with fuel economy? Buy a Honda Fit and rent a truck when you need it.