Quick SG Question
 

Current tank I have trips averaging 60 MPG, some at 55 and some at 65.

Currently if I check how many gallons to fill up it says 1.3 for 101 miles. If I round this up it comes to :

101 miles / 1.4 galls = 72.14 MPG.

That can't be right ?

Nobody else, must be me then ;)

Anything is possible, but realize that when you fill up you can be off a lot. My truck can be off as much as 3 gallons from the first click to when I actually SEE the fuel at the filler neck. You really should run the tank down to about a 1/4 or less for best results and then work on trying to get consistent fill ups.

The SG has a few things that can be tuned so be sure to check to make sure your speed is correct, type of fuel, tank size, engine size, etc. All those could give erroneous results.

My little 3 banger car can get incredible fuel mileage over short distances per the SG, but I use it as a guide for the overall tank. It all averages out in the end. Sure i could report 250 mpg over .01 miles, but that would not be honest.

Metro - thanks, I'll check the speed. George (also a little 3 banger BTW :D ) has a collar in the filler neck to stop people putting in diesel by mistake - diesel nozzles are larger than petrol ones here and George was also available in Diesel for a while. I fill up to the top of that collar each time so I know the fillups are consistent. Not always the same pump though, but I usually go to the same place and it is all flat.

Its just if I take the miles from the ODO and divide it by the gallons the SG2 says I have used on Fillup (I don't confirm at that point, I just take the reading) it comes to 70+ MPG. But no trip average on the SG2 has been over 65.

So the same instrument is giving me two different readings.

When I do fillup I found it was 3-5% out and I adjusted it halfway each time. I reset it last time though because it was suggesting I was getting 100+ MPG trips which was impossible as the first bar on the fuel gauge went out at ~ 100 miles - other owner experience ranges from 100 to 150 miles for the first bar.

A SG is only as good as its calibration, so calibrate the car and the SG against a GPS and correct for the distance difference.

Dunno how it is on a gas car, but on my diesel, the SG is calibrated to the driving style as well.
Changing the driving style, the SG will be way off.

First, (unrelated to your SG) if you have an evaporative emissions system on your car, be careful about filling right to the top of the filler neck. You could flood the system and do some expensive damage.
As for SG, what is it saying for your tank avg. mpg? Does your SG odo match up with your dash odo? It sounds like a calibration issue to me. It took me quite a while to get mine set and I still have to adjust it from time to time cause it seems change.

I have a question for all of you ScanGuage guys : Do you leave the thing plugged in at all times ?
I have a SuperMID which is much like a MPGuinio and your ScanGuage, but the backlit display stays on even when the car is off.
I barely ever drive my car. How long would you go without unplugging your ScanGuage ?

Apologies, been busy this weekend so no posting.

Recalibrated the speed based on the Go! GPS built in. We'll see. More info below.

More info and clarification for the above - When I do the miles on the ODO vs the gallons to fill up on the SG2, the figure falls. At the start of the tank it can result in an MPG figure of over 70, and maybe later it drops to 65 or less.

I always round up, so if the SG says 2.2 gallons to fill up, I take it to 2.3. Its important to stress here I'm NOT actually filling up at this point, I just use it to monitor a tank seperate from the tank MPG.

I think this variation at the start of a tank has bvggered up my calibration - it was 3-5% out on a tank which is OK for me. However because we have had some time limited offers of discounts on fuel (supermarket offers 10 pence a litre off if we buy our weekly shop there but you have to use it in a week) I have had some tanks of only 1/3 or 1/2 normal length. So when I recalibrate at fill up it went out - for example it would record trip AVG figures of 80+ MPG, when I knew there was no way it could have been better than what I normally get, maybe 60-65.

Yes, it goes off by itself after a few seconds. Sometimes if I switch off at lights I've found it doesn't come back on by itself, I have to hit the red button. Maybe a timeout issue.

Arragonis,

Hate to thread jack here, but I saw your mention of your dash camera in another thread. I don't have enough posts to be able to PM you so I though I would mention this here.

You mentioned not being able to set the date on the camera. You may already be aware of this information, but there is a website (Blog really) where the guy explains the clock setting procedure for many different kinds of inexpensive Chinese dash cameras. If you"re interested Google techmoan. He does a lot of great reviews on this type of camera.

Sorry about the thread jack

Kirk

My understanding is that the "miles left" or Gallons to fill" are workng on the avg mpg and the instant mpg.
If you start 'city driving' to find a gas station at 50 miles left (after a 5 hour trip at 57mpg for example) then the new mpg(city driving) of say 25mpg, will erase the 50 miles left almost instantly.

imo, there is a matrix that wieght the instant mileage heavier as you run low on gas.

Thanks for the info. The format of the file is the key thing.

Agreed - the Gallons to Fill should be based on what it thinks you have used since the last fillup.

Figures for what I mean - this is calculated on ODO miles vs gallons to fill, I recorded the result but not the miles / galls inputs because I am a muppet :rolleyes:

27th Sep - 77 MPG
29th Sep - 72 MPG
30th Sep - 69 MPG
1st Oct - 64 MPG
2nd Oct - 58 MPG

It consistently does this. Try it. After 1 day, record your trip ODO and the gallons to fill on the SG2. You don't actually tell it you have filled up (don't press Done), press the red button and go back to gauge. Repeat the next day and the day after etc.

You will be a Basjoos on day 1, and by day 5 back to normal :D

I did when I was using mine (had to switch to an UltraGauge because of my lousy eyesight).

"Coincidentally," I was having a problem with the Cabrio such that if I didn't drive it for three or more days, the battery would wind up dead. Since the poor thing toughed out a flood many years ago, I presumed it was something deteriorating in the electrical system. Never could find anything specific, so I just made it a point to drive it every couple of days or throw it on the trickle charger if I wouldn't be driving it for a while.

"Coincidentally" is in quotes because:

1) When the VW died my brother loaned me his HHR until I could make other arrangements. Of COURSE I moved the SG to that vehicle, and guess what? Its battery was dead after not driving for several days.

2) The UltraGauge manual mentions that constant polling can keep some devices "awake" and using more juice than they should after the key's removed. The UG has a parameter that changes the polling delay for vehicles where that's a problem (the default is to wait six seconds after the ECU shuts down before polling begins).

So my THEORY -- and that's all it is -- is that, on some vehicles, the SG can keep some or all modules active after the ECU shuts off, which can drain the battery relatively quickly.

Barring that, as far as I know the SG uses very little power and you'd be okay leaving it plugged in for a good while. For someone who "barely ever drives their car," unplugging it or trickle charging would probably be necessary even without the supposed polling issue.

I have no experience with the SuperMID but the backlight staying on constantly doesn't seem right. What does the manual say about that? Is there a timeout parameter you can tweak?

At any rate, I'd think the same would apply: If you're not driving for an extended period, either unplugging it or providing a maintenance charge will help save your battery. It would come down to how much current the SuperMID draws while the car's idle.

Anyone else know more about this (or care to correct anything I've said)?

Rick

My SG shuts down maybe 30s after engine shut down.
It stays connected all the time. No issues there.

UG killed the battery in my brand new 2009 Vibe when I left it "sit "for 6 days.

SGII has "sat" in same 2009 Vibe for 3 weeks un-used without any problems.

Another question, my SG2 shows MAP as a positive number up to 14.17. I don't have a turbo. Is it just converting -ve to +ve ?

Hi there,

At T5-Board / Board I read that a SG2 uses 35 mA of current when 'off'. Someone claimed his battery was flat after two weeks of not using the car. So there may be an issue with SG2 too, but maybe a lesser one.

I will disconnect mine when not using my van for longer than, say, a weekend.

So Long,

Tinduck

I solved my original problem, its about the low volumes being used in the calculation. When you have used 1-2 gallons each .1 the SG reports may be .1 above or below, not sure how it rounds to 1 decimal place. But it can make a 5-15% difference in MPG calculations.

As you use more fuel the .1's become less significant.