scanguage accuracy
 

I calculate my last 4 fillups. They range between 31.5-32.5 (80% highway)

How I calculate?
When I fill up my gas I reset the odometer an divide by how much gas I have to put in before the gas pump stops pouring ( I always use the same gas station). Anyway I get about the same 32 mpg, so my method of calculation is pretty decent (nothing is perfect).

I drive 25 miles each way. Today (first time using) scanguage II is giving me an average of 25 mpg (90% highway). This must off by atleast 6 mpg. I understand it gets it information from the sensors which is not 100% accurate.

Anyway my main reason for getting the scanguage is to see @ which speed do I get the best MPG on a level highway. Inaccuracy isn't as important as consistancy, hopefully I'll be able to see what consistant speed do I get the best MPG. So far the best steadiest (more than 10 seconds) mpg @ highway speed reading is 27-29 mpg.

Have you properly set & calibrated your scangauge, and do you enter your fuel fillups into it?

There are settings to calibrate the speed reading, engine size, tank size, and when you fillup you can modify the value of fuel it thinks its used so it can calculate a variance for your vehicle.

-Jay

your SGII directions dictate that it must be calibrated. on your next fill-up, adjust the gallons used screen, then it should be more accurate.

edit: looks like Jay just beat me to the response.

I've found that even with calibration, I'm still not confident in my SG as an accurate measure of FE. It's generally off by 1mpg. Granted, that's less than 3%...

Anyway, it does seem consistent enough to do the job of helping me compare. It also does all its other jobs, like telling me that my IAT is up pretty decently high with my grille block. :thumbup:

I think its almost impossible to get the MPG readings 100% correct with a SG, but you can get it within 1 or 2 MPG.

thanks..i'll calibrate.

don't forget to input motor size too. I know it is in the procedure but that one really bit me.

It's incredibly accurate for me. My last fillup was SG 12.01 gal, pump 12.00. The one before that was SG 12.62, pump 12.60.

I think you can calibrate it to within a couple of %. Being as I have a 5.7L engine in my vehicle, and a fillup can be as much as 26 gallons I have a larger margin of error.

-Jay

my accuracy isn't so great but it doesn't pick up my DFCO and the amount that I do that isn't consistant enough for an offset to work.

still good enough for me.