Overhead MPG reading?

[FordCowboy]

So I know these things aren't extremely accurate and the best way is to calculate it. I also know that some chips can alter the reading to read better. Mine wasn't working when I bought the truck, so I found the thread on how to solder some stuff on the circuit board and it fixed it. What I'm wondering is can doing this make it read even more incorrectly? I am also wondering how off can you expect these things to be? The reason I ask is because like I said mine is working now, I have run it around town only no highway and it is reading 17.1, which seems high, haven't calculated anything yet. It is also hard for me to calculate it correctly since I have 35's and the spedo is uncorrected. So I know from experience with a friends 99 that with the spedo uncorrected the readout will also read low, his was reading around 12 avg and after being corrected reads around 15avg. So I keep thinking WOW if mine is reading 17 city uncorrected that is awesome. So I guess I'm just wondering how far off can I expect this to be and possibly what those of you with the readouts are seeing on your trucks.

[99bigred]

never used with the stock ones but i have a scan gauge that plugs into the ECU and it is fairly acurate, usually on a whole tank it comes down to
+/- .5mpg

[FordCowboy]

99bigred what are you getting for MPG's

[99bigred]

city 13-16 (avg about 14 city)
highway 15-17 empty 15-16 towing (3500lbs est.)

[NCHornet]

Mine in stock mode is always within 2/10 of a gallon, with my 80 econo it is off +2, 60 tow about + .5, and with the 120 race I am about where stock would read. This all varies by truck, I have seen some stock trucks off 2 mpg. Try resetting it a couple times. I doubt you are getting 17 with 35" around town with no gear correction. Run it for three or four tanks and check by hand, usually they are off the same amount and then it is simple addition or subtraction off the display number. I can get 15 around town and country driving, and I have a DRW with 4:10's, but I have mods to help with mpg.

NCH

[cstroke69cpy3]

my overhead lie o meter shows 14 mpg to 14.6 mpg all of the time

I always hand calculate mine and am almost always above that.
i've gotten as high as 22 mpg on a trip..
probably average 16- 18

[DieselFord]

Originally Posted by 99bigred

never used with the stock ones but i have a scan gauge that plugs into the ECU and it is fairly acurate, usually on a whole tank it comes down to +/- .5mpg

Are you talking about this unit ?
ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool
I got one some 3 weeks past to work on and clear a CEL.
Have found using the MPG GPR or even the HP (not a true reading, but a display of the rate of fuel to RPM) help me find the sweet spot for mileage.
It boils down to the time or money, AKA fast and expensive or a little slower and save some fuel.
Calibrating ones right foot is the clue.
Yes there is some calibrating the ScanGage when one installs it, the instructions are clear and easy to do, note use the diesel A setting.

Doe any one know what it takes to add in the factory cruse control or install a after marke unit ?
THANKS

[99bigred]

Originally Posted by DieselFord

Are you talking about this unit ?
ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool
I got one some 3 weeks past to work on and clear a CEL.
Have found using the MPG GPR or even the HP (not a true reading, but a display of the rate of fuel to RPM) help me find the sweet spot for mileage.
It boils down to the time or money, AKA fast and expensive or a little slower and save some fuel.
Calibrating ones right foot is the clue.
Yes there is some calibrating the ScanGage when one installs it, the instructions are clear and easy to do, note use the diesel A setting.

Doe any one know what it takes to add in the factory cruse control or install a after marke unit ?
THANKS

yes that is what im talking about...im allitle confused on what you are trying to say there??
the only things dont work on mine are coolant temp and fuel pressure.

[Dirk]

With stage 3 injectors, tow tune.. my reading says 34.7mpg.


I don't think I trust it.

[fordmike1]

My overhead reads any where from 19.9 to 21.2mpg but calculating it out I get about 15.5 to 16.0mpg. I have 315/75-16 tires and my superchips is set to safe tow mode.