how to instant mpg from elm interface free
 

I have been racking my brain trying to solve this puzzle.

I have a laptop, and i have an elm interface. I am not a computer programmer. I have tried several free software programs, and none of them offer "instant mpg" or gph.

If i pay $70-$100 for a fancy program, this information is available. However, i am too cheap to spend that kind of coin on this sort of project.

Obd ii data logger will export to ms excel, but i'm not sure if it will export live data...and if it does, i don't understand how to have the data show up in excel. I could do the calculation using the maf and the vss in excel if i could figure out how to get the data there.

Anybody have access to a free program that will show instant mpg or gph using my elm interface? or a program that is free that will allow excel to do the calculations?

This cannot be nearly this difficult!

thanks

lapeer20m -

I have this setup, but I don't use it for day-to-day stuff :

http://ecomodder.com/forum/showthrea...ging-1781.html

I was trying to figure out an MPG algorithm too, but I gave up. I do think I could infer MPG by cross-referencing the LOD and RPM OBD-II parameters to a BSFC chart for my engine, but I haven't gotten around to it.

CarloSW2

i read your thread before i started this one. Doesn't really solve the issue of an instant mpg readout using my laptop elm interface and freeware

lapeer20m -

Ok, that's why it sounded like such a familiar problem.

If you want an instant readout, you need to program it in the software. If you have something that generates output data (aka in Excel CSV format), then for instantaneous MPG you *still* need to program something that consumes that file in real time and spits out the instant MPG.

Does your car have a MAP or MAF sensor? As you have already read, I have the no-fun MAP sensor, so I don't have an easy MPG algorithm.

CarloSW2

ok, so not exactly instant mpg, but i did find a simple method of logging my data, then later putting that data into excel.

the example given on converting maf and vss into mpg is in reference to a gasoline engine running at 14.7?% air/fuel ratio. The ratio for diesel to air is not necessarily constant, which should account for part of the inaccuracy of the mpg number i am calculating.

Comes out to an average of about 25 mpg....i would like to think this number if off by at least a factor of 2.

I should be able to fill up sometime in the next week so i will be able to figure my actual fuel economy. Then perhaps i can edit my formula to better reflect actual mpg numbers. Once i get the formula *calibrated* I will be happy.

Does scangauge use vss and maf to calculate mpg on all vehicles, including a tdi?