Hello everyone! I recently bought a scangauge II and have been using it for the past week or so. However, I am doubtful of its accuracy when it comes to judging mpg, gph etc. On my last tank, it said I had about 40 mpg average, however, my actual mpg was around 30!! Is it normal that it's that far off?? Do I need to calibrate it or something? I have the right fuel tank size and engine size, so I don't know what else I should do? Also, when it reads my mpg data, sometimes on the highway it says I'm getting a steady 60-70 mpg in fifth at cruising speeds, this seems to be much too high in my opinion, is this normal? Do I have a defective unit? If anyone out on the forums has experience with this product any help would be greatly appreciated!

My specs on the scangauge are: 1.5 liters for engine size, 12 gallons for tank size, and my data rate is on "fast." Also, that gauge is currently being used in an 06 xA.

Once again thanks for reading,

- Charles Lhermitte

 

You might want to check your owner's manual, I seem to recall that we have an 11 gallon tank. That would sure screw with your numbers.

 

the 60-70 mpg is correct. but its also wrong at the same time. it shows you the mpg at that split second. so lets say you are going 70 mph and there is traffic up ahead so you let off the gas, engine is at 1k rpm but you are still going 70 mph. according to that data at that second, you will get 60-70 mpg. if you get back on the gas, that number will go down.

its more of a guide to show you what mileage you will get if you continue to drive like that. its not really meant for an overall mpg.

it hold no memory for the gauges so it does its calculations every second with each update.

hope this makes sense, if not let me know

 

In reality, if you drive it right, you CAN get 40 or more mpg.

If you key in the wrong gas tank or engine size, yeah it will be off, but like the guy above it gives an instant and average. Plus you need to run a tank, fill up and key in the menu you filled up and how many gallons to calbrate it.

Mines would go to 9999mpg when I let off the gas and engine braked.

 

we have 11.9 us gallon gas tank

 

You need to keep updating the ScanGauge in order to keep it calibrated. Take your gas tank down to about 1/4 tank, then when you fill up, go to More > Fillup and enter how much fuel you just put into it (make sure the number matches exactly how much fuel you entered). Then use the next tank, and do the same thing. It should now be much closer to knowing how much you actually have in your tank. It took me 2-3 tanks before it finally got to where it needs to be. The only problem, is that it bases your current MPG off how you did on your last tank. I had one tank of 100% HWY and got 32MPG, then the next tank was all aggressive driving, and it said I got 23MPG but actually only got 17MPG.

There is a % correction, I've found that mine varies between 18-32%, with the usual setting at 20-23%.

If you don't calibrate the ScanGauge fillup setting everytime you put gas into the car, the reading will be incorrect. I missed one fillup and it threw everything off. It thought I had 26 gallons in the tank and said I was getting 50mpg .

 

Hello eveyone,

Thanks for all the replies. I'll try calibrating it over the next few tanks by adjusting the fuel consumption and I'll post again with my results. What really threw me off about the gauge is that I would purposefully rev the engine high (at 4-5k rpm) and it would still insist that I was getting 40mpg which would drive me crazy since that was obviously impossible. I understand what you mean by it giving instantaneous mpg (dm/dg for calculus fans), but what also threw me off is that I would maintain a constant 4-5k rpm over a minute or so and the damn thing would still read 40mpg. However, as I stated I've only had it for a week so I will definitely try calibrating over the next few tanks.

Thanks for all the help, it was much appreciated!

 

i love my scangauge but i only use it for clearing codes from friends cars and using the speedo, water and air temp, and voltage.

i have mine mounted just above my rear view mirror so i can see my speed while looking for cops that might be behind me

 

Yes, calibrate it at every fill-up. Also, you might need to correct the speed. Get up to 50-60 MPH and put the cruise control on. Then use a GPS to get a REAL reading of your speed. Then go to the speed setup screen on the SG2 and it will show what speed the engine computer "thinks" you re going. If it is off, press the buttons on the left or right to adjust it until it reads the same as the GPS. The adjustment is in 1 percent increments.

 

I have a tom tom GPS, would that work to calibrate it?

 

that will help to calibrate it yes, have another person help you out with that part just to be on the safe side... (one person driving, while the other is calibrating)