Yes I know about the calibration procedure, I just re-read the book for the 10th time in fact, lol.
The first fillup you hit done, then next time you adjust the value to match it up.
Everytime I've done that I've had to keep adjusting and keep adjusting each fillup after that because the values never matched. Like it would say I consumed 7 gallons but I acutally consumed 10, so I adjusted, later it would say I used 8 gallons but actually used 10, so adjust again. Eventually it got to where my calibration value was like 65% so I just reset the SGII and started over. Went through this twice now...
probably a stupid question but, are you filling your tank consistently? stopping at the first click after filling on the lowest setting always works for me.
also, I have found that EOCing or neutral coasting threw mine way off too. the neutral coasting tank that I did said that I should have gotten 43MPG for the tank and I actually got 36ish. that really threw me off and the neutral coasting was a lot of work for not a lot of reward for me. that may also be the case.
this is a weird one.
Be the change you wish to see in the world
I added 1 to the speed value because my tires are a tiny bit bigger, somewhere I found a signature link that led me to a tire size calculator that gave me the value. I'm running stock height tires, but a 205 width instead of 185, so it was just a tiny bit taller.
I don't always fill at the same station or same pump, but I always fill on slow and stop when it clicks off. My manual MPG calculations are always accurate (or at least, a lot more accurate than the SGII)
The most annoying thing is I only fill up every 2 weeks or so, so it takes me like a month to try and dial it in.
I was thinking that 3+ gallons of difference was a lot of difference between stations.
I would think that either EOCing or neutral coasting to be a better culpret, do you do either of those?
But according to his post he is using more fuel that the scan gauge is reporting if it were because of EOCing it should be showing that he's burning less than he's actually put in.
As far as neutral coasting it may actually use more gas than if he used DFCO. I tried neutral coasting in my '88 Escort for a while and saw a drop in FE.
Sounds like maybe you need to call Linear-Logic and see if they have any idea about what is going on. After my first tank in my '97 Escort mine has always been within 1/2 mile per gallon. Maybe there is something wrong with the calibration in your unit.
There isn't anything in the manuals about the CUTOFF setting, but from reading on SG's website they say it should be set at the idle TPS reading +4. Set one of your gauges to read TPS. Let the vehicle idle without touching the throttle. It isn't always zero for all vehicles. If your idle TPS = 1 then set cutoff to 5, if your idle tps is 5, set it to 9, etc. Hypermiling will throw the SG off. EOC, neutral gliding, and DFCO can all throw it off. The best way to calibrate your speed reading is to compare the speed reading to a GPS, and set the variance that way.