Does resetting the ECU improve mpg?
 

After I had installed lightweight aftermarket rims and new tires I noticed a significant drop in mpg and did as much research as I could to fix this. I slowly raised my air pressure to 50psi and kept using the hypermiling tips I had learned to at least get my mpg back to where it was before. I couldn't wait any longer for my tires to break in so I searched the internet and found out about resetting the ECU here.

Most performance modders will reset the ecu when they install new equipment so the computer can relearn the drivers habits and get use to the new mods in the car. I wasn't sure if my slightly bigger (went from 16" to 17") rims yet lighter would be a candidate for this, but I tried it anyway. Didn't seem like there was much to lose.

Looks like it worked! I notice a change in the gear shift a bit earlier and keeping the rpms a bit lower. I checked my scangauge to make sure the settings didn't change and I seem to have gained the 3-5mpg I lost when I changed the tires and rims. :thumbup: I'm still not sure if it really did the trick, I guess I won't know until the end of this fillup.

I hope it only gets better when my tires break in! Has anyone else tried resetting their ecu after doing warm air intakes or anything else?

Sometimes new cars can be too smart for their own good, ;)

I guess everything needs a good reboot these days.

Generally rolling resistance goes down as the tread wears, at least on truck tires.

Also a larger diameter rim, while lighter in mass, may have more inertia (not a factor for steady state cruise, but more energy to accelerate).

But in a steady cruise, the bigger wheel will use less power to travel further, right?

Hey got any picks of the new rims installed?

I seem to have gotten good results from resetting my ECU after modding my intake (cold to warm), so at the very least, you aren't crazy.

I can't imagine any "setting" or variable in the ECU that would care about tire size or a change of tire size. Did your overall diameter change? This could show worse mileage due to odometer/speedo error.

If you went with a lower profile tire and kept the diameter the same it shouldn't have affected it. If bigger overall, you will drop a little in FE.

bigger diameter and lower profile tires. But the tires are a bit wider than the previous ones.

Konig Daylite - Black Wheels - Wheel Size & Price Details - 1010tires.com

with bridgestone fuzions 215/50ZR17.

When my battery went dead (oops, forgot to turn off the ingition after an EOC into the garage) the ECU reset as it would.

The biggest bummer was having the TCU relearn the "fuzzy logic" in my transmission habits. Not that it has a way to figure out that it's coasting with the engine off (it has a tough time with that), only acceleration and shiftpoint behavior. It slowly re-learned and life's good again.

RH77

EDIT: Nice Wheels! I vote for pics on the car :thumbup:

Well, since you requested it.

http://img93.imageshack.us/img93/1561/newwheelsuz6.jpg

There isn't as much distance between the wheel well and the tire as it looks (I knelt down to take the pic), but I will lower it eventually.

Niiiiice wheels, look great on that car *drool*

I second that! Very nice touch. Thanks for the pic :thumbup:

RH77