Ok Gang...I got the ScanGauge II dialed in perfectly and extremely accurate now. I know exactly how to do and make the adjustment so it right near perfect. Fillup Procedure.1. Pick a fuel station that you going to use for a calibration fill point.2. Pick a pump that you going to use for filling. You must return back to the very same pump in the same direction!3. Fill the tank on the lowest sped possible of the pump this reduces foaming of the fuel.4. When the pump shuts off. That's it! Hang up the nozzle! Don't round up to the nearest dollar...5. This you go through the fillup process but leave the setting alone. Don't change the offset percent. But you can change the price value!6. Drive the truck far amount of distance at least 1/2 tank to 3/4 of tank.7. Return back to your fuel station to the same pump in the same direction.8. Fill the tank again in the same manner. When the pump stops hang up the nozzle.9. Now do you fillup and change your offset gallons to match the pump. Now be smart If you get 18.889 Gallons make sure you round up on the ScanGauge II to 18.9 gallons. If the hundredth placement is less than 5 don't round up. Say it was 18.810 you would of set 18.8 gallons.Speed Procedure1. Use a GPS or barrow one from a friend.2. Take a ride with the MPH display up on the ScanGauge II and verify the speed is correct for all speed. (25, 35, 45, 55, 65, 75, etc.)3. If not correct your ScanGauge II speed to match the GPS (not the stock speedometer!).As for verification... :thumbup2:I went back now for the 3rd trip to the very same station filled up again. Same pump and same direction. The pump stopped exactly on the amount of gallons the ScanGauge II displayed. Not to mention the price was exact too. Just doesn't get any better than that!Failures...I've seen several people get upset about ScanGauge II not being accurate. Most of the time you find out they are using any old pump and rounding up to the nearest dollar. You must use the same pump for calibartion as I'm finding out even though all pump have a weights and measure sticker meaning they are calibrated but most pump are not absolutely exact. So Station A might be +0.1 Gallon off when you go to station B it might be -0.1 off. You must use the same pump. As for direction some of the station have a slope away from the pump so if you in a different direction then it might change the level of the tank! Direction is important too. As for the speed this is how ScanGauge II gets its mileage so if the speed is wrong then the MPG figure is wrong too. MPG = Speed (MPH) / Flow (GPH)For example19.6 MPG = 55 MPH / 2.80 GPH So if your flow calibration is done poorly then the flow number is skewed. If your speed calibration is done poorly so your mileage is skewed... So if both are poorly done well you going to be very upset to find out you hand math and ScanGauge II are a long ways from being close! Oh... If you do hand math to verify the ScanGauge use the miles from the ScanGauge not the odometer. Like on my truck I'm close but not exactly perfect on the speed I'm still off by 0.5 MPH so the Scan numbers are slightly off from hand math done with the odometer but the hand math of the ScanGauge II is fine...

Now if the pump has been calibrated since your last fill-up, could this skew the accuracy of the test. It's been a while since I noticed, but isn't there a sticker on the pump of the last calibration date ?

The stickers should be dated.

Now if the pump has been calibrated since your last fill-up, could this skew the accuracy of the test. It's been a while since I noticed, but isn't there a sticker on the pump of the last calibration date ?

The stickers should be dated.

Dave is right... The sticker should be signed and dated at least month/year.

My SG is fairly close on my Jetta, but each little bit of error is a big percentage since it's only a 14 gallon tank. It was much more accurate and easier to calibrate on the 21 gal tank I had on my Tacoma. My 05 doesn't report fuel usage consistently or accurately, so it's impossible to calibrate.

I take the time to top off my tank until it's about a half inch from the top of the filler neck. That shouldn't be a problem as long as I use the same fuel dispenser the same direction, should it? Sent from my DROID X2 using Tapatalk

Yes it will be a problem. It best to let the pump stop on its own... Because one time you might get a bit more in and another time you might not. That was a problem I've ran into and bounce up and down through the offset value every time I would load with fuel. I found if you let the pump shut off and leave it alone it will hit the mark each time.

I guess the problem I have is that I see a lot of variables by only stopping at the first click off. The angle of the nozzle in the filler neck will change the height of the fuel that is required to trigger the nozzle. Also, unless the fuel station has variable speed turbines in the tank, the number of diesel fuel customers at a given time will affect the GPM of the fuel being dispensed, which in turn affects when the nozzle is triggered. I don't mean to argue, as it obviously seems to work for everybody, but I don't see how filling up until the fuel reaches the TOP of the filler neck each and every time wouldn't work. This method FILLS the tank to the same spot EVERY time. To say it doesn't is like saying filling a Pyrex measuring cup to the 16 oz line isn't giving you 16 ounces each and every time.Sent from my DROID X2 using Tapatalk

The only thing I can explain it away is the air bubble space in the top of the tank that may or may not come out during fill from tank tilt... As for pump flows... Most of the fuel station out here only have 1 or may 2 pumps... So flow won't change much...This has been the only way I've been able to get the ScanGauge II to hit the same number twice dead on. So just trying to make it as fool proof as possible.

Yeah, I guess an air pocket trapped somewhere away from the filler hose could be the problem.Sent from my DROID X2 using Tapatalk

Here is a picture of at least my 35 gallon fuel tank...So just because of a bit of slope or maybe weight in the bed might allow you to fill one of these voids so now with a extra 0.5 to 1.0 gallons could really possible change you calibration.

So My SGII is out of my gasser & is now going to be full time in my truck, how do I set it for diesel?Thanks,Dave:thumb1:

Just setup up the engine size (5.9L), fuel tank size (34 or 35 Gallon), Fuel Type is (Diesela), Fuel Cutoff is (0)...Now calibrate both the speed to a GPS and the fueling calibration above.

My Scangauge shows my best fuel economy is running in D at about 2000 rpm. But the actual numbers prove otherwise. Why would it not show accurate numbers on my truck but on yours it does? Seems like the greater the load on the engine the more accurate it is.