Archives

ok, so after reading the threads here I know what I did wrong. I hit the fillup button, then I saw "x gallons" so I entered how many gallons I just added.

As you can imagine, my mpg was way off this morning.....:(

So, now I know that this is for offset only - but how do I know what amount to enter?

I don't understand your situation, Dixonge. Was this your first adjustment to the fill amount? If so just ride it out for 2 or 3 tanks, adjusting each time, and it will balance out.

If you're asking what number you should enter at each fill up, grab the gallons value from your fuel receipt. If you fill 9.123 gallons round it to 9.1 on the SGII.

I keep a running tally, per tank, of actual gallons, and scangauge gallons, adjusted backwards for the offset. That is, I record 10 gallons actual, and 9.2 un-offset SG gallons, with my 8% standard offset. I just keep my offset near that calculated average offset between the two. It comes pretty close, and there's no variation with a short fill or pump differences.

My last three tanks:
Real SG
9.12 7.99
10.57 10.19
10.93 9.96

Total: 30.62 vs 28.14, for an 8.1% offset. That's +8.1 on the fuel side. For unrelated reasons, I keep a 1-2% negative offset on speed/miles, to match reality.

I set the tank size according to the manual which is 15 gallons for the FEH. The speed adjustment is where I find it needs to match the vehicle's OD. In my FEH, in order to have the SGII tank miles match the vehicle trip OD, I had to adjust the speed plus 1%. This still puts the SGII short about .5%, but if I adjust the speed at the next % choice (2%), the miles are higher on the SGII.

The problem with my FEH is I can fill the tank short of the 15 gallons or over as much as 2 gallons. When the Miles to Empty on my vehicle hits zero, from experience (running out of gas) I know I have 1.3 gallons left. This remaining fuel in the tank matches on average what I can add to the tank (13.7 gallons) to fill to 15 gallons. Many times I can't add the amount needed to have 15 gallons available in the tank.

After going 45,000 miles using 3 Scangauges, I find the best way is to match the speed setting so the distances match on both the SGII and the vehicle OD. After all, we're talking about MILES per gallon, not how many gallons we can add to a fuel tank at each fill-up. If you can't get your speed setting to match the vehicle OD, use the gallons used on the SGII and divide by the miles on the vehicle OD. Now that the newer SGII has fuel-cut capability, this should give you a much closer MPG figure.

Keeping a running tally of how many gallons you add to the tank and how many miles you traveled overall is the bottom line for a long term calculation. However, I want to know where my MPG stands on a day to day, trip to trip and instant basis to see the effects of my techniques in the conditions I'm driving in.

GaryG

I don't understand your situation, Dixonge. Was this your first adjustment to the fill amount? If so just ride it out for 2 or 3 tanks, adjusting each time, and it will balance out.

If you're asking what number you should enter at each fill up, grab the gallons value from your fuel receipt. If you fill 9.123 gallons round it to 9.1 on the SGII.

OK, here's the scoop.

I just got the SGII. On my SGI I just hit Fillup>Done. I never calibrated. I didn't know you could!

So, what you are saying is that I should fill the tank, and then go to Fillup on the SGII and put in the amount of gallons of gas that I just put in the tank?

I did that yesterday, and this morning my MPG for the trip was about HALF the usual numbers. I don't think it is possible for it to be off by that much.

I set the tank size according to the manual which is 15 gallons for the FEH. The speed adjustment is where I find it needs to match the vehicle's OD. In my FEH, in order to have the SGII tank miles match the vehicle trip OD, I had to adjust the speed plus 1%. This still puts the SGII short about .5%, but if I adjust the speed at the next % choice (2%), the miles are higher on the SGII.

So I should get to a certain speed, hold it steady and then watch the SGII to see how far off it is? Then I add or subtract that difference (expressed in percent) under the Speed setting?

The scangauge speed setting is the same adjustment that affects miles. So you can just check your odometer/tripmeter against the scangauge and see if there's a difference. Say you check it after 100 miles, and the SG is reading 102, then you need to adjust speed by -2%. Or if it's reading 98, then you need +2%.

So I should get to a certain speed, hold it steady and then watch the SGII to see how far off it is? Then I add or subtract that difference (expressed in percent) under the Speed setting?

No, Andrew is right, but what I did was go a full tank of gas and compared my SGII tank mileage to my vehicle's tripmeter. With that many miles (say 600 miles) on the tank, you get a better number to compare to. At 600 miles say the SGII tank mileage reads 588 miles, this means your ~2% under the tripmeter on the vehicle. Change the speed adjustment to plus 2% adding 12 miles to the SG tank trip the next time you fill up after 600 miles. This should adjust your SGII tank miles to match your vehicles tripmeter much closer. If the SGII would let you adjust the speed % to the tenths, you could almost match to the mile.

Personally, I wouldn't go by the actual speed OD to adjust percentage of speed higher or lower on the SGII. I certainly would not change the speed percentage with the number of gallons I added at fill-up. Once I adjust the speed based on miles traveled, I make no other adjustments at fill-up because the tank size never changes once set. The tank size is just to give you how many gallons are remaining from the amount you set for the size tank. If you set the tank size at 15 gallons, the gallons used will always add up to the remaining gallons to equal exactly 15 gallons.

GaryG

Dixong, if it was that far off it almost sounds as though you went back to fillup after having pressed it once before. If the display showed 0g or something close to it, it was already reset. If you then upped the number to what you filled, it would think you were consuming at twice the rate.

When you fill up, you should see the number of gallons the SG thinks you used -- you can then adjust a percentage to make that number match the actual fill amount. If it is really that far off you could just pretend you filled again and then reset the percentage to 0 and see if that fixes it for you. If the percentage is currently at 200%, you'll know what happened. ;)

Doing an offset when adding gas will screw up a single tank of gas mileage. It will throw off every trip reading including Current, Today, Previous Day and tank reading. My advise is to keep the size of the tank the same and match the speed to the vehicle OD.

Changing at the tank fill is how Debbie Katz and myself got a 7.5% MPG decrease in our SGII reading at the Hybridfest MPG Challenge. This took my MPG down to 57.5mpg when it should have read 61.8mpg according to the factory navi reading if it had gone that high. Debbie did not max out the navi at 6ompg, so I was able to compute my mileage based on her Navi and SG readings.

GaryG