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My Sg said that I was logging 53.1 MPG and I thought that I was having a great MPG week. I pulled into the same gas station that I usually fill up at but had to use a different pump than I usually do. After filling up I calculated that I only got 51.6 MPG. Damn! I got bit by the "different pump monster"! I didn't recalibrate the Sg though as it has been dead on for the last couple of months.

Hmm... I think most of us would agree the best way to measure is to fill it up to the neck of the pipe. In other words top off.

Though you should try to see where the car col filter line is.

I assume that Kurz lives in an area where they don't have automatc shut-offs which pretty much prevent filling up to the the top. I also asume that where Kurz lives they have discovered how to eliminate any metering differences in the pumps.

I will drive to Fairfax the next time I fuel up!

Actually... We do have automatic shut-offs.
The problem lies with when the automatic shutoff kicks in. This is what changes pump to pump.

The amount measured in dispensing the gas doesn't change.

And yes I have to pump about 25 - 30 times to get it up to the neck. Since every .1 of a gallon the shutoff kicks in.
Tedious yes, but at least I get a few more days between fill ups and a more accurate MPG.

Sounds like a lot of work to me Kurz and possibly some wasted fuel. I let it shut off once by itself and then do it twice manually - then I'm done. Don't think that the possibiity of being sued deters the Pakistanis who dominate the convenience stores here from running out and changing the pump settings as soon as the inspector leaves. I have heard one story here from a blogger in Kansas City who says that he encountered 3 stations where the pump showed $1.50 as soon as it came on without a single drop having been pumped.

I used to fill to the neck, taking about 20 "clicks" before getting there. Then when I bought another car, the salesman suggested stopping at the first auto shutoff because overfilling could mess up the stuff that handles overflow and fumes. When I changed my routine to exactly as yours, jstol, two more clicks after auto-stop, I immediately started getting better mpg (and no, not just on that first fill, which obviously indicated higher mpg, but all of them since--May to today). I really believe that topping off was somehow (and I have no logical reason what that may mean), was resulting in wasted fuel; i.e., fuel not contributing to powering the car. I haven't topped off since, and I won't. As far as the problem with using a different pump, the only significant effect that might have, IMHO, is the grade of the drive where you park to fill. If it's a downward slope away from the fill neck, you'll probably get more fuel in the tank before auto-stop than if you're sloped the other way.

Any pump you suspect of foul play, and you can raise high holy
hell with the local bureau of weights and measures.
.
_H*

I think that if you try to squeeze too much fuel into the car some of it goes out the overflow and is wasted

Hi Jstol3:

___The fuel is not wasted, it is burned later via the vapor recovery system.

___Good Luck

___Wayne

I just go until it clicks the first time. All that means is that I get a bit more variability in the measurements. But there are lots of other things that also contribute to that variability, so I don't worry about it. It all averages out in then end.