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View Full Version : Re-Calibrating MPG Display


907DAVE
Tue, November 24th, 2009, 02:25 AM
Ok..... so going out on a limb here, can you calibrate the Average MPG display? There must be a Fuel Flow map in the PCM that controls this, but can it be changed? The reason I ask is because after switching to Hybrid injectors my display has been almost exactly double the actual mileage. Looks pretty sweet when it shows 40 mpg, but not very practical. I assume it's because the injectors moved twice as much fuel as before. With stock injectors it was pretty darn accurate, and kinda nice for road trips. Made it easy to estimate fuel stops and helped me adjust driving styles for better economy. I guess it would take alot of trial and error to get it close but would be worth the effort.

Any ideas?

soutthpaw
Tue, November 24th, 2009, 10:00 PM
I am not familiar with any way to recalibrate it exactly... however my recent set of tunes was spot on when I filled up today where as the previous set which had some of the same tunes was off by 2-4 miles a gallon... I was using several different tunes on one tank too as I did about 250 miles of pulling my 3500 lb trailer

Oh ill take some of them 40mpg injectors too :smiley_roll1:

907DAVE
Thu, November 26th, 2009, 01:17 AM
Yup.... I noticed that when running certain tunes that the display will read closer to actual MPG's. Can remember but I thing that the "HOT" tunes would show higher MPG's than the "LESS HOT:D" tunes. Hmmmmm..........

Power Hungry
Sat, November 28th, 2009, 03:52 AM
The OTC is calibrated with a fixed set of maps that feed off vehicle speed and pulsewidth. The problem now is that with your new injectors, your pulsewidth is about half what it was before so your OTC now reads twice the fuel economy. Unfortunately, there isn't any way to fix it. :shrug:

907DAVE
Sat, November 28th, 2009, 03:56 AM
Darn....well it was worth a try. Thanks for the response.


Dave