: Callibration of gas meter?



harrynw
10-17-12, 05:27 PM
My 2010 fuel meter is a little optimistic. It said I had used 16 gallons and averaged 24.5 mpg for the tank. When I filled it up, it took 17 gallons, and my actual milage was 22.5. I couldn't find anything in the manual showing how to callibrate the sensor, or whatever is telling the computer how much gas is being used. It is not off a whole lot, but if you were low and thought you had a gallon more left than you actually did, it could cause some problems.
I have had other similar guages that you could set the actual use, and it then callibrated itself based the difference between the 2 values, and after a couple of settings they became very accurate.

Anyone know about this?

PJ1520
10-17-12, 06:13 PM
Harry........the DIC average miles per gallon calculates actual miles driven versus actual gallons used. It is accurate, needs no recalibration. Your manual calculation is what can be off, plus or minus. You are calculating actual miles driven by how much fuel the pump/you put back in the tank, not how much you actually used.

Gas pumps can vary anywhere from a couple of tenths to a couple of gallons as to how much fuel they will deliver to the tank before they automatically shut of. The pump therefore does not necessarily put back into your tank the exact mumber of gallons you used. It could put more back in, or less.

In the example you gave, your pump might have shut off automatically a tad early on the prior fillup. Then with the next fillup, another pump made up the defecit from the previous fillup (or you did by squeezing in more gas after the pump shut off).

Pumps vary from station to station and even between pumps at the same station. Over the course of several tanks of gas calculated manually, the (accurate) DIC calculation will be nearly exactly the same as your manual calculations.

By the way, doesn't the DIC (Drivers Information Control) on your GenII SRX provide you with the distance to empty? The one on the First Generation SRX does.

My low fuel light goes on with about 50 miles until empty and the DIC assumes I will continue to average the same average MPG I have been until the tank is empty. I have gotten mine down to "zero miles" to empty, but on the refuel the tank took on 18.8versus a gas tank capacity specification of 20.

PJ

harrynw
10-18-12, 06:08 AM
I have only filled it twice, and both times the actual milage was 1-2 less than the average shown in the DIC. I had reset the average when I filled. Its not a big deal. The longer I have had this car, and the more I drive it, the more I like it. Getting 22.5 mpg doing 75 mph is something I can live with. The final test will be pulling my boat, which weighs 1,800 lbs with trailer, so it should be well within its capabilities.

TheCaptain
10-18-12, 07:16 AM
Also, filling the "dual tanks" is a bit tricky to get them filled to the same point every time. I have done it a lot though, if I fill to the neck (which you're not supposed to do, I know) I can get accurate measurements. The pump will kick off at different times before the tank is full (because the one tank has to fill the other).