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I went and finally filled up the tank for the first time after buying the Scangauge II. I've filled up and gone through one whole tank with it, and so I was finally able to calibrate the device.

According to the Scangauge II, my average gas consumption was 14 MPG... however, through my manual calculations, 242 miles on 11.571 US gallons equals 21 MPG. In order to make it show that I actually burned that amount, I had to adjust it by -25%.

All this time the Scangauge II has been off by 25%?! How is that even possible? Is it due to the rate at which the Scangauge II can update the display? I got it set to "Fast" and to me at least it looks like it's working fine. How would I be able to tell if the setting is not right?

Interesting. I would say double check your base settings (engine size, etc.) and see what happens on the next fill. Part of this may be a bit of variability from one fill to the next on the part of the pump. You shouldn't have to put up with anything as crazy as a Prius tank bladder but even my Accord was off by +/- 5% or more on a regular basis. Even so, my calibration factor with that car was only 4-6% at the very most.

I just went out and checked it, and for some reason it was all on default settings... yet I'm poitive I had it all set up right from day one. It thought the Camry had a 3.0L engine and a 15.0 US gal. tank (though it's actually 2.2L and 18.5, respectively). So yeah, hopefully this should help.

I wish it could calibrate itself. ;)

http://www.scangauge.com/support/pdfs/SGMan5_0.pdf

Covered completely in the directions. The MPG is based off injector time, and distance travelled. Since distance can be off due to tire pressure, all these little things need tweaking, and there is NO way to have it "pre-calibrated"...

Probably the best directions I've seen on a mobile device - the directions sold me on the part. Now that I have my WideBand O2, I can start saving up for my ScanGuageII.

I have an obscenely complicated and obtuse spreadsheet to calibrate to the nearest thousandth of a gallon ;)

holler if you want it.

11011011

I went and finally filled up the tank for the first time after buying the Scangauge II. I've filled up and gone through one whole tank with it, and so I was finally able to calibrate the device.

According to the Scangauge II, my average gas consumption was 14 MPG... however, through my manual calculations, 242 miles on 11.571 US gallons equals 21 MPG. In order to make it show that I actually burned that amount, I had to adjust it by -25%.

All this time the Scangauge II has been off by 25%?! How is that even possible? Is it due to the rate at which the Scangauge II can update the display? I got it set to "Fast" and to me at least it looks like it's working fine. How would I be able to tell if the setting is not right?

Be sure to set the fuel-cut setting correctly. For a Toyota you most certainly have dfco in your engine. Without this value being set correctly you will appear to use more fuel than reality. The value should be your idle throttle position plus one (Use the TPS gauge)

Then be sure to fill the tank correctly so that there are no air pockets.

I calibrated mine against the car's native computer. That was much easier.

I never set my fuel cut-off, but I KNOW that my car has it... of course idle throttle is 0, I guess that would do it. All that being said, I've gotten consistant results (winter/summer)with a 2.5% offset. But right now the SG2 is in my girlfriends 2000 jetta TDI which I was recently doing work on (timing belt, MAF sensor).

My first fill was off 10.5% today. Hopefully that will be my only calibration needed that is so large.

My first fill was off 10.5% today. Hopefully that will be my only calibration needed that is so large.

Don't be surprised if you see a big jump when going from E-10 to straight gas or vice versa.

Don't be surprised if you see a big jump when going from E-10 to straight gas or vice versa.

I'm up around 10% now and have been on E10 since at least the first of the year. Before that, I was usually around 7-8%. So E10 makes a difference in the SGII calibration?

Thanks,

Rick

The Scangauge only know gallons. It doesn't know what those are gallons of. Since ethanol has lower energy per gallon, your offset needs to be more.

According to http://en.wikipedia.org/wiki/Fuel_efficiency
Regular unleaded gasoline: 125,000 btu / gal
Ethanol: 84,600 btu / gal
So, a 10% ethanol mix will have about 125000*.9 + 84600*.1 = 120,960 btu / gal, which is about 3.2% lower. That matches your change from 7% to 10% offset.

Nice thread resurrection.....

But, good to know I'll have to recal when I come off winter fuel. Which can't happen soon enough. However, pricing looks scary! Usually, winter fuel costs less...... so, Premium for me could easily reach $3.75-$4 a gallon.... considering that it is $3.36 now:(

Don't be surprised if you see a big jump when going from E-10 to straight gas or vice versa.

I only use E10. I've been thinking about experimenting with E30 to see if the FE goes up or down. A new study suggest that it might go up.

I would have to mix E85 and E10 to attain an E30 mix. Not very hard to do if you can find the E85 pumps. Currently my closest one is 25 miles, but that may change soon.

Presumably, it will go down. Alcohol has less energy than gasoline.

Presumably yes, which is why it was a suprise that in each of the 4 cars they tested it peaked above regular unleaded at E20 or E30 depending on the car. Basically just before the fuel had enough ethanol that the fuel trims maxed out and caused a CEL during WOT testing.

Interesting read. It was paid for by a pro ethanol group so take it for what it is worth, but the testing looks pretty good as far as how they did the tests.

http://www.ethanol.org/pdf/contentmgmt/ACE_Optimal_Ethanol_Blend_Level_Study_final_12507.pdf

What they left out is probably more important. They only did Highway FE testing and they didn't publish the dyno results. Interesting, nonetheless.

I notice you're running a Mazda 5. Have you tried installing a short ram intake for improved intake airflow? Many of the import tuner performance tricks will provide benefits for hypermilers. Particularly relating to intake/exhaust and aerodynamics.

Modifications to improve fuel economy:

Aerodynamics - yes, IF they're for reduced drag and not for increased downforce. Downforce mods will increase drag and hurt FE.

Intake/exhaust - generally no. The higher-flowing intakes and exhausts will help peak high-rpm power, but hurt at low rpm. It's been months since my engine saw over 2,500 rpm, off the bottom of most dyno charts even. If an intake is sized for flow at 6,000 rpm, at 2,000 it's taking in only 1/3 of the airflow. A tiny straw is enough for that.

Intake/exhaust, anything that improves the flow of air through the engine should help. Remember, it is basically an air pump;) Any restrictions will hurt.... let it breathe freely. I haven't found any problems at the lower RPM.

Yep.... downforce mods would be bad.

For rweatherford, I think I found the answer:
Low carbon number alcohol fuels methanol and ethanol can give more power when burned than conventional gasoline (petrol) fuel. The performance benefits come largely from the high heats of vaporization of methanol and ethanol, which give strong charge-cooling effects, and the increased octane ratings.

What they also didn't include was the fuel analysis on their alcohol blends. The additional alcohol probably raised the octane rating and the cars' ECMs advanced the timing. This could be the reason for the increased MPG. If you're burning 87 Octane normally..... then I could see where you might see something out of this.

I'm with PM on intake and exhaust mods. IF done properly they can help, but most performance mods are for upper RPM ranges. If our engines were designed to maximize power in the 500 to 3000 RPM range it might be better than purely trying to increase total HP, which is what most aftermarket mods do.

A lower grille block would be easy and I'm considering it but my wife drives the car some and I'd be concerned about temps this summer, so that is on the back burner.

Yes the higher ethanol content creates a higher octane. 10% increases normal gasoline blends by 2 points. 87 becomes 89, etc.

My guess is the cars ECU is on the limit of adjustment and perhaps runs lean sometimes, but I'm just guessing. It is difficult to believe, but I may try when I get an E85 pump nearby. They didn't give the HP graphs, but I'm not sure why this is important for FE results if what really matters is how much fuel is consumed during HWFET testing.

The Ford Fusion as I understand it basically has the same 2.3L as my Mazda5.

They didn't give the HP graphs, but I'm not sure why this is important for FE results if what really matters is how much fuel is consumed during HWFET testing.Because.... it would show any hp loss & you wouldn't want a car that got 50MPG but couldn't pass a tractor trailer.... or a plain ole tractor.

Well, if your readings are off go back and check all your settings, engine size, fuel tank size,etc. That will cause the readings to be off.

Be sure to set the fuel-cut setting correctly. For a Toyota you most certainly have dfco in your engine. Without this value being set correctly you will appear to use more fuel than reality. The value should be your idle throttle position plus one (Use the TPS gauge)

Then be sure to fill the tank correctly so that there are no air pockets.

I calibrated mine against the car's native computer. That was much easier.

Shrek,

I found your information interesting, since I'm having some initial problems getting my SGII to agree with my manually calc MPG. I have lots of faith in the manual MPG since they are based on lots of data.

On what source do you conclude that the dfco should be set to throttle position plus 1? I will look for this setting which I cannot find covered in my manual, but then the manual is pretty dense information. If I understand, then the dfco setting is accessable from the TPS guage? Didn't think I had seen any access "arrows" when that guage was up. I must be misunderstanding you somehow. Help please.

What does it mean to calibrate against the car's native computer? I'm afraid I couldn"t get that from the manual either.

Thanks.

The fuel CUTOFF setting in the SGII should be set @ your normal idle TPS reading +1 from logic & experience.

DFCO is a vehicle computer control. The SG's fuel CUTOFF attempts to recognize this mode of operation.

He calibrated to the OEM MPG computer in his vehicle.

Thanks 2Way. I appreciate your efforts to educate me. I suspected that that the setting of the dfco had been derived experimentally, but it is nice to have the confirmation.

As others have done, I did some experimentation with the SGII display to try to discover a direct relationship between the display of 9999MPG, that being dfco I think, and could find no display parameter which seemed to exactly correlate in time. I suppose that this situation may occure due to delays in sampling and display, but that is just a guess on my part. I would guess that if this were the case, then raising the sampling rate to the highest value would show a more direct relationship between TSP and dfco.

And, I cannot find a ref in my owners manual to changing the setting for dfco. The manual seems a bit difficult in the more complex operations since it is not indexed. Could you give me a clue where to find the coverage of dfco changes, or in the absence of manual coverage, how the change is made?

Thanks again for your interest and the other great contributors at this site!

I'd have to look... as I recall... it is in the Fuel Setup and is labeled CUTOFF.
Yes, there seems to be a slight delay on the CUTOFF vs. OPEN LP display.

Thanks 2WAY. dfco was right where you indicated.

The SGII was set to dfco of 24, which I assume was a default value. The Echo idle TSP is 11, so I set the dfco setting to 12. Am I right? My manual doesn't seem to cover this adjustment. At least I didn't find it grouped with the other "fuel" adjustments. Maybe my version and my manual don't match.

12, you are right. CUTOFF was a late addition to the SG & the info wasn't included in the manual.

OK I have read several of these but I have a Manual trans on a Diesel engine. I have a scanguage ii (3nd day) and have noticed the following when I am coasting in gear the MPG went to 9999 I then changed the CUTOFF value to 28 up from the default 24 and that went to 3500 MPG when in gear. When I shift to neurtal the MPG reads between 250 and 300 MPG which seems more right to me. So should I keep changing (adding) the CUTOFF value or set it to zero. Also it seems to me that I should continue to shift to N and not stay in gear. I will look at the excel file that was posted when I get thur the first tank.

My head hurts

Kevin, does you VW TDI show a value for TPS? If it does, note what it reads at idle, and then set the fuel cut off to 1 above that for a starting point. If it doesn't have a TPS reading, then further experimenting along the lines you are doing are going to be needed.

Yes it does show Tps which went to 0 when I coast both in gear and in N. So I need to set CUTOFF to 1.

Be sure to set the fuel-cut setting correctly. For a Toyota you most certainly have dfco in your engine.
Where do I find that setting in the scangauge?

01VWBUGTDI, I am very interested to hear what your GPH (Gallons pr hour) number on a TDI is.

I suspect that for a TDI the consumption at idle is so low that chasing fuel-cut is just not worth it, and one might just settle for P&G and NICE-On coasting alltogheter.

Nerdyguy. The fuel-cut is somewhere in the setup, but I don't have the unit here now. It is easy to find, if it is there (only in the newer SGII version)

01VWBUGTDI, yes TPS +1 or 2. I am noticing that, on rare occasions, TPS will bump up one on heavy decel (the throttle opens just a little more). So, I have gone to TPS +2 vs. +1. In any event, you want to go lower in CUTOFF value vs. higher. If I remember correctly, CUTOFF is in the FUEL setup.

Shrek, I tend to agree. My idle GPH is like 0.15-0.18. I usually make use of DFCO for off-ramp braking and stop lights i.e. for more rapid braking vs. a coast or glide. Obviously, much easier in a standard.

I will update MPG as I get a few tanks in but my first 1/2 tank using at or below speed limits and coasting in N gave me 52.3MPG. I have noted that my GPH at idle is .13 except when the A/C is on (this is Texas in the summer) it goes to .26-.29. I had to drive my truck today to move some stuff at work so I did not have a chance to change the TPS to +1 or +2. Thanks for the input.

KP

Kevin, I did not need to change the DFCO setting for the SG to correctly register DFCO on my TDI. I believe it's at the default setting of 24. By the way, mine reads 0.6-0.7gph at idle when fully warmed up. I don't bother with FAS except for long lights or long downgrades, but I do use DFCO whenever it makes sense to do so -- especially since the TDI will DFCO all the way down to 1100 rpm or so.

By the way, after you burn through a few tanks I'd be interested to hear how accurate the SG is for you. Mine is very non-linear in its behavior: by that I mean that it over-reports fuel consumption on the highway (i.e., at higher rpms) relative to fuel consumption in town. If I calibrate the thing so that it reports accurately in town, it will report a highway tank as 35-38mpg rather than the 45-50 actual mpg that I see at the pump. If I calibrate it so that it reports accurately on the highway, it will report a city tank as 55-60 mpg rather than the 40-45 actual mpg.

I reported this problem on tdiclub a few months ago. It appears that the SG may not be pulling all the data (like fuel temp) that it would need to accurately calculate TDI FE under various conditions, but the thread seemed inconclusive as to whether this affects everyone or not. I ended up with a headache and no closer to a solution.

I did not have a chance to change the TPS to +1 or +2. It is CUTOFF you change. Change it to the value of your idle TPS, plus one or two.:)

i myself is kind of dumb to this. What is idle TPS and how do i find out what it is? when i do, is that what the fuel cut off # is?:confused:

If I remember correctly, CUTOFF is in the FUEL setup.
Can you find the page in the manual where it is?

WRICONSULT "Mine is very non-linear in its behavior:..."

I was not to happy to see this.

I did get a chance to set CUTOFF to +1 then +2 and I still see very high numbers on MPG when I am in gear and I am coasting towards a red light. When in N I still see 150MPG to slightly higher which still seems good. So I guess I will continue to drive like I have been with the exception of using the A/C (use in the afternoons not early in the day). I will coast in N towards red lights and green lights that I do not think I can make. I will drive the speed limit or -5MPH of the speed limit. I will coast on hills and off ramps in out of gear. When filling up I will use same pump facing same way filling in the cool of the day and let the pump cutoff three times as I know Diesel foams on fill. I will watch the first few tanks (this may take some time as I only drive 30 miles a day). I will replace airfilter maybe with a higher end one. Then I wll hit the excel file that was uploaded by Dan.

Thanks to every that replied.

KP

When I fillup on my Civic, I don't enter the pumped gallons into the SGII (I just enter the pumped gallons that the SGII thinks it should be). For some reason, the fillup is very inconsistent even using the same gas pump and orientation. Before I had the SGII, I had to use 2-3 tanks in order to get an accurate FE calculation and I've found that the SGII is accurate when comparing to multiple tanks. I rely completely now on the SGII.

equlizer, you read TPS (a standard OBD PID reading that the SG is already programmed for) while you are at idle, then add one or two to that TPS number and that is what you want to set the CUTOFF setting to. You have to know what your throttle position (TPS) is at rest in order to set the CUTOFF.

n3rdyguy, it isn't covered in the current manual.

K done! Thx :) what does this do anyways? I dont notice any difference though.

By the way, after you burn through a few tanks I'd be interested to hear how accurate the SG is for you. Mine is very non-linear in its behavior: by that I mean that it over-reports fuel consumption on the highway (i.e., at higher rpms) relative to fuel consumption in town. If I calibrate the thing so that it reports accurately in town, it will report a highway tank as 35-38mpg rather than the 45-50 actual mpg that I see at the pump. If I calibrate it so that it reports accurately on the highway, it will report a city tank as 55-60 mpg rather than the 40-45 actual mpg.I'm using my SGII in a Honda Fit and I have some similar questions. The SG appears to be giving me unusually high or low numbers as well, and the difference is between city/secondary driving and highway driving just as you noted. Which one is right? I guess I'll have to wait until I can do some full tanks under one set of conditions or the other, and compare the SG's mileage to the actual fillup figures.

WriConsult can split the difference between City & Highway and it won't be quite as drastically off. Still, that's a pretty wide % band that it is off by.

Yes, wdb, best to do it by actuals. Also, make sure you have the correct engine size programmed.

My scanguage is now 100% accurate with tenth of gallon. and factor was 3.4% with speed adjustment.
Now, I can calculate 100% right MPG and my olds 2001 intrigue 3.5 V6 gives average 34 to 35 MPG. Goes over 515 mile full tank with 17 gallon size.

Review of TPS Cutoff Property settings.
"0" TPS is 12 at idle but at highway driving, it can be ~ 15 @ 3,000 rpm. Therefore it is necessary to have a higher cut nevau instance, some 16, it should probably not be much higher since it can result in an error at very low accelerator pressure ie. <16 TPS

I filled up for the first time today and did the more>fillup> and adjusted mine to match the actual fill. It calculated the MPG to be just over 36mpg which is almost identical to my calculations on paper. Not bad for the first tank on a new SG. I have my tank size at 12 Gallons, Cutoff at 19 and have not touched the speed.

The main thing I use my SG for is trying to find sweet spots between IGN, TPS, RPM and MPG. I'm still not sure what's the best style of driving for my car as even before I started slowing down and emplying some basic hpyermiling techniques my MPG was not that much different (gained ~4mpg). I think this new Toyota engine 2zre-fe with the dual VVT-i is interesting how good the impg gets when the IGN is 30+

I'm on my second tank, will the distance to empty become more realistic over time?