This has been sorted out many of times which is why you haven't gotten a timely detailed response. I suggest start your searching at cleanmpg.com but to answer a few of your questions:

- mpg = miles from car odometer/gallons filled, but the SGII does its own calculations from the ecu.

- the 2007-2008 fit do not have a FCD and the 2009 FCD is off(optimistic) by about 5mpg.

- SGII gives a lot of instant feed back, what you choose to do with that info is up to you, I will say that you don't need a SGII to get better mpg.

- Technique is key - I cannot stress this point enough and no one said it was easy(technique that is).

Doubt will lead you to the truth in this case, trust me I am a hater!

 

OK, no gauge in the earlier models. The SG is difficult to calibrate, from what I have read, so that makes it dubious. There is no substitute for the miles/gallons formula to check the SG. That is how you determine if it is accurate. Otherwise it is just numbers on an LCD.

My actual comparisons between the FCD and actual indicate ~2MPG in my case. That is only two tanks so far and I will keep watching it.

In the sum up it looks like I can get the same benefit from the built-in FCD.

 

P&G really does provide an improvement in fuel economy. But it's laborious and most folks don't stick with it for very long because of that. Plus for most folks it does take some practice before they start seeing big numbers. I tried it for a while but it drove me nuts so I stopped.

I have a buddy on these forums, richxku, who got 55 MPG or so using P&G and other stuff (like driving with the windows up and no AC in the summer, doh). He gave up on the more radical things and still gets 44 MPG regularly. Someone else hit over 60 MPG. I average about 40 MPG but then I have a heavy foot and I like to drive the same speed as the rest of traffic. (I'm pursuing stuff such as aerodynamic improvements and lower rotating mass as ways to improve MPG and reap other benefits as well.)

ScanGauge is a mixed blessing. Whatever you do, don't take the instantaneous MPG figures as gospel, and if you use P&G don't trust the trip figures either. They both tend to be wildly optimistic. As for calibration, in my experience there is no way to get it to read correctly for everything. Your best bet is to calibrate it for the number(s) you find most useful and treat the rest of the numbers as relative figures.

If I had a GE I'd play around with the onboard electronics before spending extra money on a ScanGauge.

Filling up a Fit is, uhm, interesting. The GD folks regularly squeeze 12 or more gallons into the so-called 10-gallon tank. That much extra capacity means that "fillup" numbers become highly dependent on the pump you use and when it trips off. Folks trying for repeatable, accurate MPG figures usually continue to fill the car until they see gas in the filler neck (I have taken to calling this "hyperfilling".). Getting that much gas in the car can take quite a while, but it also means fewer fillups.

A search of the fitfreak site will provide you with a lot more information on these topics. There's also cleanmpg.com if you don't mind wild-eyed idealogues with no sense of humor. They wrote the book on hypermiling, P&G, all that.

 

i have my scangauge display rpm, speed, real time mpg, and current trip mpg.

such a frickin awesome tool. OP: glad you finally got one

 

My second tank was 37.8 without any of this foolishness. I have <600 miles on the car. Playing weird games on fillup will give wildly erratic results. I just do not let them top it and keep track over every drop that goes through the engine. I did this with a '96 Dodge diesel for 12 years and can account for every drop it burned. I got accurate mileage figures. To my way of thinking this is the only way to know how you are doing. I might get 50+ on a fillup if I am on a slope and the tank does not get filled properly. And then I can tell everyone that driving with two hard-boiled eggs in the glove compartment made it possible. However, until I can do that consistently the claim is dubious.

I have been down the "miraculous mileage" road a few times. I have read some wild claims. I know of no one who can consistently beat the laws of physics. If these folks with P&G have been able to I am sure they have kept accurate records for each tankful over a period of months. If they have I would be impressed.

BTW, anyone driving a 2-stroke SAAB is beyond redemption. I owned two, and there is no excuse for that kind of stupidity. ;o)

 

Does anyone have the latest version with xgauge? If so can you check to see if the short and long term fuel trim codes work (you would have to add them using the xgauge tool).

I have an older version and really need this info but dont want to pay the money to upgrade it if it does not work.

Any help is much appreciated. Thx.

 

That's why people fill till they can see it in the filler neck -- to eliminate the wildly erratic results they get otherwise. It's the only way to ensure consistent fillups in the GD Fit. Dunno about GEs on that score.
They have, you would be. Search, search, search.
It was a 4-stroke, the German Ford V-4 they went to late in the 95/96 series run; some Sonnetts had the same motor. I drove some smokers, notably a sweet little Monte Carlo, but never owned one myself.

And I gave up on redemption shortly after my 14th birthday. It's been downhill ever since for me, in that regard.

 

^^^^^ Re Hypermiling: I am sure these folks are getting good mileage. I doubt very much that P&G has anything to do with it. No matter how it is done, the same amount of weight has to be moved the same distance. It is achieved by the heat in the fuel. While fuel is saved in the "glide" portion, it is consumed in the "pump" when the mass must be overcome and returned to a higher rate of speed. More fuel is used to regain lost momentum than to maintain momentum.

I think the better mileage is due to the other measure used. As I said, I got ~38MPG on my second tank at <600 miles on the car and doing nothing special at all. This is in town and highway driving.

If I try this technique and raise my average MPG to 50, I am saving a penny a mile. Hardly worthwhile for other than bragging rights. I would save enough in a year to buy a nice set of floor mats.

SAAB: The German Ford (Taunus) V4 the used started initially as a test engine for evaluating the move to four stroke. The V4 was an industrial engine, I believe. Anyway, some bright Swede suggested that rather than develop an engine of their own they might just as well use the V4. They were strong engines and the Sonnet with one was a pretty hot little car. And a very safe car. That is the story I got way back when I was suffering from SAAB fever.

 

Therein lies the rub. IC engines are more efficient at wider throttle openings; therefore, by using no fuel during the glide and more efficient throttle opening during the pulse, overall fuel economy is improved, especially when compared with running at a steady state and low throttle opening. It really does work, it's just an enormous hassle. I went back to the cruise control after two weeks, but still do some of the other techniques such as running higher tire pressures and popping the car into neutral when the oppportunity for long glides presents itself. Plus I use "maintaining momentum" as an excuse to howl around corners, muahahahaha.

This was all a much hotter topic when gas was $4-ish/gal.

That rings a bell; something they used to power portable electric generators, that kind of thing. I can state from experience that it was mechanically tough (but cursed with Bosch electrics).

 

The only bad thing about scanguage is people get obsessed and next thing you know they are going well under the speed limit and it takes them like 5 minutes to get up to speed from a light... so frusterating to get stuck behind slow moving, slow reacting people. No amount of fuel is worth that lol

....and return to eco talk

 

There are always efficiencies which vary with RPM and load in an engine. These are revealed, I guess, in the torque and HP curves. And I do not doubt for one minute that the Fit, and many other, engines have a peak efficiency band. What I remain unconvinced of is that this efficiency band in the "pulse" phase outweighs the losses incurred during acceleration. I do not think anyone has addressed this. It is assumed that "P&G" is the cause of the efficiency. I counter that I could do all the same tricks used other that the "P&G" and get the same mileage. And I could claim it was because I keep two hard-boiled eggs in the glove compartment, the moon was in the second house, I use only Chevron gas, Mobil-1, or, and this is the true clincher, have owned a SAAB. There is no real way to prove or disprove it. No one is comparing using the tricks with and without "P&G" so the argument that "P&G" makes a difference is unproven.

I understand that folks have a lot invested in this belief. And I am not going to change their minds. They are convinced. But until I see "P&G" compared to non "P&G" in the same circumstances I cannot accept the idea as other than wishful thinking and the fond belief that somewhere there is a free lunch waiting for us.

 

There are other considerations to take when you are using the Scangauge. In the trip screen what you see is an Average compensated MPG. What this means? let say you are driving from point A to C, from point A to B you get 10 MPG average, from point B to C you get 20 MPG. The average between the 2 is 15 MPG. The average compensated could be different and all depends on how long did you averaged 10 MPG and how long did you averaged 20 MPG. If you averaged let say more time 20 MPG then your average compensated could be 16 MPG instead of 15 MPG. If you stayed more time on 10 MPG compering to 20 MPG, them you average compensated could be between 10 to 15 MPG but not 15 MPG.