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Third time in a row I've had to adjust the fuel usage % at my fillup. Each fillup I adjust to match the gallons I just pumped. After the second fillup I would have thought it would be pretty well calibrated.

Last fillup I had to increass a whopping 7% more. I'm on like +17% now. Last tank used a lot more pulse and glide than on the first two tanks.

It seems the MPG estimates of the SGII vary a lot with driving style and I have to wonder how accurate this thing is (not very).

Or, maybe I have missed something important in the setup?

Any comments appreciated.

Why don't you tell us what you have setup with the SG so that we have a starting point, Also let us know if anything in particular happens during your trips.

Without some details it is hard to know if you really have a problem or not. But if you adjust at each fill up based on the difference between the pump and the sg you are going to end up jumping all over the place with the numbers. You really want to get the adjustment in the sg to be close the average tank of gas - factoring out all of the variable like how full you got the tank, if the car was on a level surface or not, and other things.

What I suggest is you track the pump amounts and the "unadjusted" sg amounts for a few tanks. To get the unadjusted sg amounts take what the sg reports and divide out whatever the sg reported for each fill up. A +9.5% adjustment means you divide by 1.095. The ratio of the pump amount and the sg "unadjusted" amounts with each summed over a few tank fulls should get you very close to the adjustment factor you want to be using for the sg. Once you have that number you can do the sg adjustment after one of you fill ups and just leave it there. Any variability between the sg after that point should be mostly due to usual variable in terms of how full you get the tank of the car each time you fill it. You can never really get that variability out of the system.

I had the same problem. It was my fault not the Scan Gauge. I was topping off the tank instead of just stopping when the pump kicked off the first time. Now I just go to the next .25 cents after the pump kicks off and I have no calibration issues. If it is not dead on it is + or - .1 gallons.

Hi all, I'm new here - got my SG last week and it's awesome! But I've got some problems with it, thought I'd post them in case anyone can offer advice.

Did my 1st "real" fillup today, the one where you enter the 1st adjustment for fuel pumped. I expected it to be off but NOTHING like what it was :( I pumped 9.637 gallons, SG estimated around 6.6 gallons used. The adjustment was 43.2%!!! I filled at the same gas station as the 1st time, exact same pump (and on the same side, facing same direction) and let the pump stop then one extra "squeeze" as I always do.

Day I got it, I set it up for my 2003 Eclipse GTS w/fuel type "Gas", tank size 16 gallons (it's actually 16.3) and 3.0 L engine. Next morning I topped off the tank with one extra "squeeze" and did the SG fillup without entering an adjustment.

I had probs the 1st couple days, SG was regularly killing my speedometer and I'd have to unplug/re-plug it to get it working again. Sometimes the speedometer would swing wildly between 20-50mph even though I was well below 35. Other times it would stay pegged on 0 mph. I'd also see iMPG as high as 40-50 mpg while accelerating UPHILL :confused: And then of course there were a few miles of driving with SG disconnected while trying to sort all this out.

Finally I found out it was because I was plugging SG in, then turning key to start engine. Found out if I turn key to "run", let the onboard computer boot, THEN connect the SG and let it connect before cranking, things seem to work right.

The "current trip" avg mpg I was seeing with 100% city driving was in the 24-28 mpg range which seemed a bit high to me...

Would these issues account for the 43% adjustment I had to make, and the too-high mpg? Most of my driving is in town and the tank mileage for this car over the last 4 years has run 21-22 mpg.

Another thing, after filling up today I went on my 1st highway trip - not far really, 104 mile round trip. I reset the car's trip meter when I filled up, and doing the SG fillup of course reset miles for the tank. When I got home, car's trip meter showed 104 miles (correct) but SG reported 53 miles for the tank and only 2.53 gallons used :confused: What could cause that?!?!! I disconnected SG when I got to my destination (hotter than hell today...) could that do it? I wouldn't think so though. Only other thing I did was, coming back I noticed that the tank miles were 1.5 miles over the trip meter miles so I entered a -2% adjustment on speed. That would have been at the 1/2 way point of the trip - would that do it?

Finally, it was all I could do today to get SG to show 20 mpg average on that drive which was 99% highway miles. Despite showing 25 mpg averages in city driving all last week. Guess that is due to the 43% adjustment I had to make this morning?

One question, obviously I've screwed something up somewhere :o What is correct procedure to start tank calibration over again? I'm guessing:

1) Reset SG to default to return tank adjustment to 0%

2) Re-enter fuel type, tank and engine size.

3) Top off tank and do fillup without entering an adjustment, to clear tank data.

4) Hope I don't mess it up again ;)

Will this let me start with a "clean slate"? Thanks for any input!

DH

Third time in a row I've had to adjust the fuel usage % at my fillup. Each fillup I adjust to match the gallons I just pumped. After the second fillup I would have thought it would be pretty well calibrated.Same thing happened to me. I finally just set it at roughly +10% and let it be wrong, but consistent.
It seems the MPG estimates of the SGII vary a lot with driving style and I have to wonder how accurate this thing is (not very).In my Fit the SG was so inaccurate when I would use P&G that it was essentially useless. It was routinely 20% optimistic. People here tell me it was me, my methods, my driving style, et alia. But I know of 3 other folks who had the same experience with their Fits (and none except me who will admit it, mostly because they are a bit too caught up in getting big MPG numbers I think). For me though it was a deal killer, and I took the SG out.

Hope you have better luck than I had. The SG appears to be a great tool for a lot of people.

For virtually any gasoline powered car you should set the SG to 'hybrid' ... otherwise you lose information during a FAS or P&G. That could explain the big swings in numbers.

DH, your mitsu computer(I'm guessing you have the v6) doesnt do well with key off. A fas switch is the only way you will get your FAS's to work properly, If you want to have it give you correct info, then you cant fas, I installed one by bypassing the ground switch for the fuel injector. works gr8.

Filled my tank yesterday and was very pleased to see it agreeing with the previous tank adjustment (+12.2%... yeah, I was shocked too). SG isn't perfect as it underestimated my gas usage by 0.027 gallons but that's within reason to me. I also have a little cheat sheet in my sun visor for gas amounts at varying levels of my tank (1/4, 1/2, 3/4) and the miles I should have on the odometer trip meter based on the estimated MPG. This way I can doublecheck the SG against the fuel gauge and see if the numbers start going astray.

Sorry to hear that it doesn't work for others. I know I could not have broken the 43mpg barrier without it and now my goal is to make sure each trip out I aim for 45mpg. This forces me to be more aggressive in my fuel-saving tactics so I've been getting in more NICE-ON's and pulsing the pedal more intently.

I heard some people still have problems even after switching to Hybrid mode. 43%? That sounds way too off. If I saw that I would reset the SGII, re-input all the data and go to the FILES section of this site and look for the Scangauge Calibration Excel sheet. Next time you fill up, use the spreadsheet and see what it suggests to adjust the tank to. Also if you are doing FAS/NICE-OFF, I'd stop and see if that makes a difference.

Here's the file:
http://www.cleanmpg.com/forums/downloads.php?do=file&id=14

DH, your mitsu computer(I'm guessing you have the v6) doesnt do well with key off. A fas switch is the only way you will get your FAS's to work properly, If you want to have it give you correct info, then you cant fas, I installed one by bypassing the ground switch for the fuel injector. works gr8.

Thanks, yes it is the V6. I'm 100% new at all this and don't FAS - barely know what that is but I'm assuming it is shifting to neutral and cutting off the engine totally to either coast to a stop, or drop to a certain speed then restart engine?

Closest I come to that is shift to neutral and coast with engine running - I think that is called Nice-On?

Anyway the #'s I'm getting from the SG are total nonsense :( Beginning with the 43+% adjustment I made last Sat after my 1st tank when SG reported I used just over 6 gallons but I pumped 9.637 gallons

Then the trip I made Sat after that adjustment, SG reported 20.5 mpg for a 104 mile trip with 99% of it on the highway. I topped off the tank Sunday and reset everything for another try, the actual MPG for that trip was 30.55 based on 3.404 gals burned over 104 miles.

After resetting the SG to factory defaults and doing the fillup procedure with no adjustments, well hey I was suddenly seeing my current avg soaring back to 30+ mpg just driving around town :eek: And my speedometer went on break again right after the fillup, I was in a parking lot within a quarter mile trying to get that happy crappy sorted out.

At this point I think I'd get better estimates by calling the Gas Psychic hotline at 1-800-GAS-MPGS, ya know ;)

Anyway, it's something interesting to do. I'll get it figured out one day and maybe even get some useful info out of it.

DH

Ok, here's what you do, go to the linear logic website, contact them and have them send you the OTHER connector. The one you have doesnt work with your car and WILL NOT. Tell them you have the mitsu engine and the connector you have doesnt work. You need the connector with all the pins.

Then the trip I made Sat after that adjustment, SG reported 20.5 mpg for a 104 mile trip with 99% of it on the highway. I topped off the tank Sunday and reset everything for another try, the actual MPG for that trip was 30.55 based on 3.404 gals burned over 104 miles.

I would not attempt to adjust the sg or to evaluate the calibration and accuracy of the sg based on such short trips. The natural variability on how full you got your tank on each of two fill ups can make a huge difference. If each fill up was off by half a gallon in opposite directions on a 3.4 gallon fill up that can come in as close to a 30% error in your mpg calculation.

I would do all my calibrations based on a close to a full tank as possible. That way the errors will be much smaller in proportion to how much gas you actually use.

Ok, here's what you do, go to the linear logic website, contact them and have them send you the OTHER connector. The one you have doesnt work with your car and WILL NOT. Tell them you have the mitsu engine and the connector you have doesnt work. You need the connector with all the pins.

I had emailed them about the probs and asking if the other cable would fix it for a Mitsu a couple weeks ago when I got the SG but never got a response.

So I called today, took several calls before the phone would even ring but finally got thru. The guy I talked with was very helpful, 1st thing he asked when I mentioned the speedometer was whether I had a Mitsu or a Hyundai. Then he gave detailed info on the cause of the problem and said he'd send me the right cable. OUTSTANDING customer service! Hopefully the replacement cable will get things straightened out.

I would not attempt to adjust the sg or to evaluate the calibration and accuracy of the sg based on such short trips. The natural variability on how full you got your tank on each of two fill ups can make a huge difference. If each fill up was off by half a gallon in opposite directions on a 3.4 gallon fill up that can come in as close to a 30% error in your mpg calculation.

I would do all my calibrations based on a close to a full tank as possible. That way the errors will be much smaller in proportion to how much gas you actually use.

Agreed. Only reason I did that was because the #'s were so badly off. I reset SG to factory defaults to clear the 43% adjustment, re-entered engine & tank size and cutoff, topped off the tank and did the fillup procedure WITHOUT entering an adjustment, like you do for the very 1st tank after installing the SG. I was hoping this would get me back to a "clean slate". Normally I fill at around 1/8 - 1/4 tank.

DH

At this point I think I'd get better estimates by calling the Gas Psychic hotline at 1-800-GAS-MPGS, ya know ;)LOL! Sounds like Dionne Warwick has a new career.
Anyway, it's something interesting to do. I'll get it figured out one day and maybe even get some useful info out of it.I hope the new cable straightens it all out. If not, you may want to try just getting the tank MPG to agree with reality and forgetting about the rest of it. If you're careful in your gauge selection it shouldn't drive you too crazy. ;)

I kept getting wacky increases each time I filled up. Chevy tracker gas tank 15Gal.. picked that from memory..
rechecked book... that's for Convertible.. kept reading..
but the 4 door is 17.3 Gal... I have a 4 door... Made the change and things are looking better..but not perfect..
mpg is always calcluated pump gallons divided by odometer reading.
Wonder if Suzuki engine needs that cable? Is it available for the asking or requires additional $$$

I kept getting wacky increases each time I filled up. Chevy tracker gas tank 15Gal.. picked that from memory..
rechecked book... that's for Convertible.. kept reading..
but the 4 door is 17.3 Gal... I have a 4 door... Made the change and things are looking better..but not perfect..
mpg is always calcluated pump gallons divided by odometer reading.
Wonder if Suzuki engine needs that cable? Is it available for the asking or requires additional $$$

I don't know about the Suzuki, but my Hyundai needed the other cable. LL shipped it to me @ no cost and insisted that I keep the orginial for use in another vechile. I got it two days after I called them.