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In my 92 deville, it said I got 17.2 mpg for my last tank of gas. I calculaed it though, and it was only 14. Also, it said there were 8.8 gallons used, but I was able to put in 10.8 gallons. Whats the deal? Either the thing is off, or I have a gas leak or something, but I dont smell gas??
 

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2005 CTS-V, 1994 Infiniti Q45
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The gas mileage calculator and fuel used are based on injector open time (so the readings should be super accurate, at least for fuel used)...... There was another thread about this sometime back, but it was only off like a few 10ths of a gallon, and we determined that much gas was still in the fuel lines.... THe key is to consistantly fill the car at the same level, IE stop at the first click, dont keep going.... You can usually squeeze more in, but IMO its not worth it.... Start doing that....
 

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my fuel used seems to be pretty accurate...... aorund 8 gallons used, it isn't TOO acurate, but when it gets to like 10 galllons or more, it is amost right ont he head.... I havn't cmfired my millage... but it seems to be pretty good..... remember to reset if after each fill up if you want to get better results (computer vs. real millage)

Wes, why do you say not to fill it after the first click? usually I do and it dosn't seem to effect the FDC or anything......
 

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2005 CTS-V, 1994 Infiniti Q45
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Well if you calculate your gas mileage the old fasion way (miles on trip meter divided by gallons used to fill up) you want to do this.... but if you rely on the fuel data center than it doesnt matter....

Plus, you still dont wanna go much farthter than that.... There really isnt any reason to...... I still will try and round it off so its a semi even number (like from 14.26 to $14.30).....
 

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lol, I am lazy and go up to the next dollar....

but if doing it manually, you generally want to stop at the first click?
 

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2005 CTS-V, 1994 Infiniti Q45
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Thats just the easiest way Ive found of making sure you consistantly fill it up the same time... It helps your mileage to be more accurate.....
 

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Under the "tune up" section of the newspaper it mentions to not go beyond the first click because it can effect the emissions devices like the charcoal cannister. There were other reasons, but cannot remember them. I always round up to the next dollar anyway.
 

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That is true, I never really thought about that..... IF you get gas into the charcoal canister, thats not good....

What that thing does is suck out extra vapors from the gas tank, and then puts them into the intake tract..... The canister saves it and deposits it into the intake as needed....
 
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