Interesting mpg performance

Ronman · May 27, 2016

Just added intake, exhaust and custom tunes. I also have 35's so anticipate to have some error in my mpg readings but this is a little crazy.
Running stock the lie-ometer said I was getting 13-14 mpg. After mods I went for a drive. It initially shot up to 24mpg (yeah right). I reset and it shot up to 99 as I was rolling to a stop. I stopped to get fuel and decided to reset as I was planning to fill up. The pump was terribly slow so I only got $30 before I gave up. Left the station and noticed my meter said 8.0 and 81 miles to empty although I was just under 1/2 a tank. I drove approximately 42 miles. Meter eventually climbed to 11.5 mpg. The strange thing is the meter only dropped to 68 miles to empty and the needle doesn't even look like it moved. I stopped twice and shut the truck off hoping to see things reset.

Is there any explaination for my readings to be this inconsistent?

CATDiezel · May 27, 2016

Who's tuning did you install?

Ronman · May 27, 2016

Written by Punch It, purchased from Rudys. It was already on the tuner when I got it.

dsberman94 · May 27, 2016

Probably because you reset it so many times so quick. The data the truck uses to compute the mpg data hasn't been given enough data to give you an accurate number. 99mpg as your rolling to a stop with no throttle input. So you're moving without any throttle. Give it more time to calculate before you start resetting things. Get some highway and city driving in. Too soon to be worried about mpg numbers after just having reset it.

Ronman · May 27, 2016

I get you on that. I was just thrown off by the whole 81 miles to empty with half a tank. I will keep my finger off that button for a while. And find a station with better pumps.

dsberman94 · May 27, 2016

23ish gallon tank. Idk what they actually are, just guessing. So just under half leaves you with just over 10 gallons and 8 mpg is what it's saying you're getting. So that's 81 miles. Not sure what's confusing I guess.

Ronman · May 27, 2016

I've never run it to empty but I can guarantee 23 gallons ain't filling me up. Let's try closer to 35-38 gallon tank. (I've never looked up the official capacity)

Ronman · May 27, 2016

Went ahead and looked it up. 37.5 gallons which means 18.75 at half a tank. At 8mpg that would be 150 miles to empty.

Which is why I was asking about the 81 miles to empty and only dropping to 68 miles to empty after 42 miles.

lincolnlocker · May 28, 2016

top it completely off and reset both trips while in park go drive it..

my 12 has funky reading from tune to tune. its punch it also.. street tune is almost dead on to what the lie o meter reads.

live life full throttle

god bless america and the farmer who feeds your fat ass

Jomax · May 28, 2016

I have Alberta tunes and my lie o meter is DEAD on, it's even more accurate then it was stock

Sent from my iPhone using Tapatalk

ImAti0n · May 29, 2016

If you have an iPhone go into the App Store and download the app "Gas Cubby" you input the gallons, cost and mileage and it does all the hand calculations for you.

TyCorr · May 29, 2016

Its fairly easy to divide miles traveled by gallons at fillup. Done. No misleading electronic voodoo.

Ronman · May 29, 2016

ImAti0n said:
If you have an iPhone go into the App Store and download the app "Gas Cubby" you input the gallons, cost and mileage and it does all the hand calculations for you.

Nice

dmd · May 30, 2016

I know most have newer trucks, but mine when the needle is at 3/4 there is half the
fuel left in the tank. After a fillup the first 1/4 goes by real slow, the the lower the tank
the faster the needle moves. At 1/4 showing on the gauge it has about 4-gal
in the tank at best.

TyCorr · May 30, 2016

Hmmmmm....mine isnt like that other than once it gets off full it seems to drop quicker. In my eclipse gsx, the gas gauges did something similar to what you are describing. We would swap out the factory 2.5k resistor fir a 3.5k and it would increase the ability of the needle to reflect the fuel in the tank. The only tradeoff was that warm, little fuzzy spot at the bottom was gone. It was running out, you had 2-2.5 gal left, the light came on, in 30 miles you were out of gas.

Apples to oranges, since the tank mods have been done mine stays on full for 100 miles.

dsberman94 · May 30, 2016

Once mine hits 1/4 tank I've got less than the 50 miles it says I have. And that fuel slosh is as wonderful as always for lying to me when I'm parked on a hill.