MPG reading on display correction

[p-Bar]

My ScanGaugeII works really poorly in my 2004. 5. I called the ScanGuageII people said that it doesn't usually work on 04 and 05's. Sometimes reflashing will work. I haven't wanted to pay for that for "sometimes". Did yours work right out of the box?

No I did have to calibrate what do you have the % figure set at in display fillup? mine is set at 129%. The key is to top off the tank or it won't be accurate

 

[AH64ID]

p-Bar. . Based on what I have been reading for the last few years your 04. 5 is a mystery as to why it works. 04. 5 and 05 shouldn't be accurate.

 

[p-Bar]

Ya I know I'm lucky if I change the percentage by 1 or 2 a fill up. I still believe if your not topping it won't be accurate.

 

[AH64ID]

I used it on my Tacoma and never topped it, was accurate. I can tell by the fuel level PID that the tank gets to roughly the same spot every time, certainly not enough different to account for 80% SG swings.

 

[BIGNASTY]

Overhead can be off but it will be the same off all the time (hope that made sense) so if it changes I know something is wrong, I hand figure my MPG and its off by about 3 MPG. But I could be wrong I have to pull down my pants to count to 21 ok 20 and 1/2

 

[AH64ID]

Overhead can be off but it will be the same off all the time (hope that made sense) so if it changes I know something is wrong, I hand figure my MPG and its off by about 3 MPG. But I could be wrong I have to pull down my pants to count to 21 ok 20 and 1/2

Mine varies from 13% to 25% off, but averages 17%.

 

[BIGNASTY]

Mine varies from 13% to 25% off, but averages 17%.

I wonder what makes it vary so much ? On mine pulling the TT its always the same, empty its the same but it doesn't vary unless my right foot makes it or if im in rolling hills. In the west its not much rolling , flat or up you know how it is in the west. Maybe air temp

 

[AH64ID]

Who know's, it's always done it that way. My dad's 06 is the same, but my bro's 06 Hemi seems to be accurate.

 

[NNovak]

I am curious if there is a way to do a full reset on the overhead computer. When I first bought my 06 with 48K the overhead was consistantly off by 3mpg. As I put on more miles it went to 5mpg off around 100k but pending on how much town or hwy I did this would fluxuat. Now I can't find any pattern with 113k and some light mods done (smarty jr, flow exhaust). Seems the more miles on the truck the more off it gets. IF it could have the long term memory erased it might be back to less off and more consistant.