CleanMPG reviews the ScanGauge II

With the advent of the ScanGauge, many now have the ability to measure their fuel economy performance in real time as simply as plugging it in and setting it.

Wayne Gerdes - CleanMPG - May 6, 2007

The ScanGauge II

The ScanGauge II is not only an attractive add-on for any 1996 and newer automobile; it is at a minimum, a necessity for those interested in increasing their fuel economy and decreasing their emissions no matter the vehicle they currently own or drive. Even vehicles with an easy to comprehend FCD (Fuel Consumption Display) like the Honda and Toyota Hybrids can be driven to even higher fuel economy with the addition of a ScanGauge II using parameters that the comprehensive OEM (Original Equipment Manufacturer) FCD’s do not include.

A few examples … Since the Prius II does not include a tachometer or discrete coolant temperature display (both are very useful to an experienced Prius II pilot), those as well as possibly Load and TPS (Throttle Position Sensor) would be a very likely set of parameters to display. For a Honda Hybrid driver who may be modding his vehicle with a WAI (Warm Air Intake), the Intake Air Temp display would be incalculably valuable to see the effects from one slight configuration change to another as well as coolant temp, TPS and possibly Load. And of course the non-hybrid drivers finally having the capability to display an i (instantaneous) and aFCD (averaging FCD) in real time although not at the same time unfortunately. These two parameters are what makes the ScanGauge II a “Must have” for both the experienced or budding hypermiler.

The HW you will receive.

The ScanGauge II, OBD-II CAT-5 data cabling, 25 page Quick Start guide and Manual as well as (2) adhesive stickers. The Quick Start Guide and User manual is not only filled with information on how to setup your ScanGauge II properly, it includes all the support details needed to use the ScanGauge II to its fullest. The Manual can be found online for your own review at the following: ScanGuage II.

Installation and Setup

1. Locate your vehicles OBD-II port under the driver’s side dash (usually) or passenger side dash.
   
2. Locate and attach the ScanGauge II to your dash or other convenient location so that you can see its output clearly with nothing but a glance but not in a place that could obstruct your standard gauge cluster or air bag.
   
3. Plug the Data cable into either port on the ScanGauge II.
   
4. Turn the Vehicle on or at a minimum; turn your Key to IG-II so it reboots all the computers and powers up your standard OEM displays. This should provide power to the OBD-II port thus powering up the ScanGauge II.
   
5. Plug the Data cable into the OBD-II port and you will see the term “Connecting” in the display as it goes “Live”.

Once the ScanGauge II has initialized communication, it is time to perform the setup for your particular vehicle.

The following screenshots are those that should be displayed in sequence as you follow the instructions beneath each to drill down to the detailed setup screen.



Push the button next to “MORE” -------------------> Push the Button next to “SETUP” -------------------> Push the Button next to “ENGINE”.


Select the size of your “Engine” by pressing the top buttons on the right or left to increase or decrease the size displayed until your engine size is selected. In this case, 2.4L is selected to match the Accord’s 2.4L. Once the Engine Size displayed matches the vehicle the ScanGauge II is connected to, press the button next to “Save”. If you do not depress the “Save” button, the Engine Size will be have to be re-entered if the ScanGauge II is ever disconnected. This may be the method of choice if you move your ScanGauge II from vehicle to vehicle.

1. Press the button next to “MORE”.
   
2. Press the button next to “SETUP”.
   
3. Press the button next to “ENGINE”.
   
4. Select the Engine Size as described above directly under the screenshot.
   
5. Press the button next to “SAVE”.
   
6. Press the “Home” button which will bring you back to the initial Selection screen.

You will repeat the above screen shot sequence to drill down to the detailed setup screen again and again …

The next setup parameter from the detailed setup screen that needs to be adjusted is “Fuel”. Push the button next to “MORE” ---> Push the Button next to “SETUP” ---> Push the Button next to “FUEL”.

1. Press the button next to “TYPE”.
   
2. Select the type of vehicle by pressing the top buttons on the right or left to show Gas, Diesel a, Diesel b or Hybrid. If you do not own a diesel, select Hybrid even if you do not own a hybrid for the ability to continue recording data points through a FAS.
   
3. Press the button next to “SAVE”.
   
4. Press the “Home” button which will bring you back to the initial Selection screen.

The next setup parameter from the detailed setup screen that needs to be adjusted is “Fuel Tank Size” from the same “FUEL” screen. Push the button next to “MORE” ---> Push the Button next to “SETUP” ---> Push the Button next to “FUEL”.

1. Press the button next to “TANK SIZE”.
   
2. Select the tank size of the vehicle by pressing the top buttons on the right or left to increase or decrease the tank size displayed until your tank size is shown. This screen cannot be sized to a tenth of a gallon so select the tank size to nearest gallons.
   
3. Press the button next to “TANK SIZE SAVE”.
   
4. Press the “Home” button which will bring you back to the initial Selection screen.

The next setup parameter from the detailed setup screen that you MAY want to adjust is “Units”.

Push the button next to “MORE” ---> Push the Button next to “SETUP” ---> Push the Button next to “UNITS”.

For English users, you do not need to change the Units. For those who would like to view Metric based parameters, press the button next to “UNITS” --> Select any or all 4 English parameters and change to the Metric display.

A ScanGauge II is actually a lot easier to setup then it appears. You find your OBD-II connector, Plug it in, 5 minutes of setup, head to the station to fill up and you are on your way other then the fuel calibrations. The fuel calibrations are performed during your tank fills.

For the more advanced users, the ScanGauge II can be calibrated even further including speed and distance to ever more accurate measurement if desired.

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What can a ScanGauge II display?

Although most here will use the ScanGauge II for its extensive Fuel Economy functions including the i and aFCD’s, it has other advanced features some will find useful at some point in the future. Let us go through the list of features it is capable of today.

ScanGauge II - A 3-in-one Automotive Computer with the following data points available to view in real time.

Trip Computer	Digital Gauges	Scan Tool
Maximum Speed	Instantaneous Fuel Economy	Reads Trouble Codes
Average Speed	Fuel Consumption Rate (GPH/LPH)	Reads conditions that set the Trouble Code
Maximum Coolant Temperature	Battery Voltage	Clears Trouble Codes
Maximum RPM	Coolant Temperature	Turns off the "Check Engine" light
Driving Time	Intake Air Temperature	Tells you when vehicle is "Ready" to pass OBDII testing
Driving Distance	Engine Speed (RPM)	Make and store up to 10 rewritable special codes to send to the vehicle computer
Fuel Consumed	Vehicle speed (MPH)
Trip Fuel Economy	Manifold Air Pressure
Distance to Empty	Engine Load
Time to Empty	Throttle Position
Fuel to Empty	Ignition Advance
	Open/Closed Loop Operation

The Details

The ScanGauge II displays 4 parameters of your choosing from the Digital Gauges column above at any given moment in time. You can change a given parameter to any other parameter within that columns display output as well as switching over to the alternate output of the Trip Computer or Scan Tool sections with the “Home” button circled in red in the lower right hand corner and selecting either the TRIP or SCAN functions. A Prius II driver might want to consider viewing the iFCD, Coolant Temp, TPS and Load. An aggressive non-hybrid driver will more then likely display Voltage (12 V), Load, iFCD and TPS.

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The Review

Although the ScanGauge II is used to build upon your FE skills in the vehicle you are currently driving, let us take a look at a safety aspect that many may not have considered? Imagine your teen or twenty-something borrowed your car to head out to the local movie theater with his or her friends. You know there is no highway travel that could possibly be between home and the theater and yet 70 mph was displayed. What do you do with the tell tale signs of excessive speed?

This type of data just might save a young drivers life with parental intervention taking place as soon as it was discovered? Of course it will record and display the distance traveled and every other parameter in the Trip Computer list but the above is one I believe to be possibly more important (albeit devious ) given it may just save a child’s life. Hopefully well before anything happens rather then afterwards …

Who would ever need an OBD-II scan tool? Everyone! I have used the ScanGauge II to diagnose and clear codes on 3 different vehicles of relatives and acquaintances. Without the ScanGauge II as an OBD-II scan tool, they would have either paid a $75.00 diagnostic fee at a local dealership or they could have only received a simple code read without reset from a local AutoZone or Pep Boys.

And what will we actually use its capabilities for? Why increasing our FE of course! For a non-hybrid driver without iFCD feedback, you are relying on a gas gauge that cannot show you a thing as it simply does not move that the eye can detect in any appreciable fashion over any short period of time. An iFCD tells you what your current FE is at an exact moment in time and you can adjust your current throttle position using this feedback to adapt to a given traffic condition all the while maximizing your current FE. Anyone that has an interest will quickly discover what their vehicles FE is at a given speed, temperature, Load, or TPS depending on the road, traffic and weather conditions around them. They will also see how FE falls during a lengthy climb or shallow hill or inside of tight or wide open traffic conditions. By adapting your current actual FE as displayed by the iFCD with one you want to achieve (within reason of course) with the accelerator pedal, you can minimize your fuel consumption. This is the most basic of descriptions but it works.

What kind of results over a complete tank? I think some will find the following ScanGauge II results shocking. My previous best tanks in the Ranger came about from long trip down to Florida and back hauling some relatives light weight “stuff” in the P/U bed.

2003 Ford Ranger P/U tank data

My previous best tanks doing all the things I normally perform without any feedback was just 40 mpg. This particular Florida trip yielded two tanks at 41.93 heading down empty and 41.92 heading back while loaded up in the warmer temps of Georgia and Florida respectively. The following tanks yielded ~ 33 to 40 mpg range until last September of 2006 when I received the ScanGauge II. That first tank while ScanGauge II equipped gave me the opportunity to adjust in real time to shallow road undulations that I had never even knew were there, adjust speeds and accel rates to mate a solid P&G cycle to traffic conditions as well as what she is worth at various speeds out on the highway.

The first tank while ScanGauge II equipped ended at 45.693 mpg. I drove one more tank as summer was coming to a close just to be sure and that one was even better at 47.111 mpg. These are actuals calculated from distance traveled over gallons consumed. Could these two tanks been short fills leading to the huge numbers? Not a chance as I always top off and the distances achieved was phenomenal for both. The first 45 mpg tank allowed a range 20 miles further then ever achieved previously at 720 miles. That 47.111 tank was over 800 miles and well over 100 miles further then anything achieved previously! The only change was being ScanGauge II equipped while using the i and aFCD’s feedback for maximum effect. Again, we are speaking about a Ford Ranger with the aerodynamic qualities of a sheet of plywood facing flat side into the wind and without any kind of i or aFCD previously. As a side note, she saw 69.x mpg in a LS P&G during that second tank that I had no idea she was capable of without the ability to optimize and see with the ScanGauge II.

Did the ScanGauge II’s feedback only work in a previously non-FCD equipped Ford Ranger P/U? The 05 Accord has an OEM i and aFCD built into the NAVI TC (Trip Computer). I won’t go into too much detail regarding the Accord’s TC other then to say its OEM iFCD has a max range of 50 mpg, it becomes more inaccurate over time with any reboot from a FAS given its slow reboot time and its bar graphs display is discrete down to a minimum of 5 mpg increments. For the average steady state Accord driver it works magnificently, but for someone with a 48 + lmpg, you can imagine where this vehicles OEM iFCD is camped most of the time as well as disappearing after a FAS for far to long a period

Accord EX-L w/ NAVI

Pre- ScanGauge II equipped Accord’s personal best: 56.9 with a string of 52 - 56 mpg tanks during the summer of 2006.

Post- ScanGauge II equipped Accord’s personal best: 58.13 mpg with a string of 56 - 58’s into the fall of 2006.

Not as dramatic as the increase seen in the Ranger but the Accord already included an FCD albeit with its limitations and no way of optimizing a P&G cycle at any speed range or rate. The maximum reach of the Accord came about after she became ScanGauge II equipped including the following from work parking lot to Home driveway w/ an ~ 2.5 mpg negative offset yielding almost 69 mpg for this particular segment home.

So it works, are there any negatives?

Like any “One size fits all” piece of HW we can purchase off the shelf or lot, there are a few minor issues … First off; the instantaneous FE is calculated using air flow through the engine, not fuel actually consumed. The calculation should yield almost dead on results with the cumulative being held by the various aFCD’s. With decreasing temperatures or the change from summer to winter fuels and back again however, the ScanGauge II has to be continually adjusted at each and every fill. In minus 5 to minus 15 degree F temps, I have seen as much as a negative 11% offset to keep the ScanGauge II calibrated in the Accord. As temperatures warm up, your fuel fill offsets will begin heading back towards parity. In 80 degree temps, the offset can be as little as negative 3% in the same vehicle. The Ranger had a miniscule negative 2% offset in 60 degree temps.

Another issue has to do with Fuel Cut. The ScanGauge II has no way to tell if the ICE is in Fuel Cut or if the car is at speed running at idle as you would in a NICE-On. Although the FE calculated and shown is very high under this condition (between 130 and 250 mpg depending on speed and ICE size), fuel is still shown being consumed when it is not thus causing an ever increasing error to build in. If you were the type to decelerate in Fuel Cut with ICE-Braking vs. FAS’ing in a very hilly or mountainous area, this error could degrade the displayed FE accuracy sharply. This is no fault of the ScanGauge II given the OBD-II protocol does not have a Fuel Cut parameter for the ScanGauge II to use for determining when you may or may not be in Fuel Cut. It is however an issue that some owners may have to live with depending on their commutes terrain.

The next small negative has more to do with the data bus speed and activity of a given vehicle rather then the ScanGauge II itself. While performing a FAS in the Accord, the ScanGauge II holds onto the current FE displayed for ~ 5 seconds even though no fuel is actually being consumed. A work around to this problem is to let the idle die off and time your Key off so that the ScanGauge II immediately goes to 9999 or at least a high instantaneous FE before actually beginning the FAS. If you are in a heavy stop and crawl with a very short span between one FAS and the next, the aFCD will hold onto maybe a 5 mpg readout for the 5 + second time it takes to pull in the new data vs. no fuel consumed in actuality all the while you are watching your aFCD fall precipitously. It is a frustrating experience but again, one that has more to do with the automobile you are currently driving rather then the ScanGauge II. In the case of the Ranger, it updates much sooner so the nagging delay while the Data transfer updates to a FAS condition is not nearly as prominent. Fortunately for automobiles purchased in 2008 and beyond are supposed to use a much faster CAN bus vs. the older ISO setup many of us are currently stuck with. With the faster data updates of the newer and faster protocol, this problem should all but disappear.

The next strike has to do with the size of the buttons. More then once I have accidentally pushed the wrong button and on one occasion, accidentally reset the ScanGauge II’s current segment. Manipulating the ScanGauge II maybe 100 times a day over a period of 6-months yielded only one reset but it was enough so that I should mention it. A number of times I have pushed a button and ended up with the wrong display showing vs. a particular parameter or display I wanted. Being a little more careful on my part would easily cure this issue but when slicing and dicing in and amongst an infamous Chicago stop and crawl, sometimes there just isn’t time to make sure you are pushing the exact button for the exact parameter when your attention is on the traffic around as it should be.

Another small hit has to do with any 1996 or later Honda with a Lean-burn ICE. Lean-burn ICE’s use upwards of a 22.7:1 A/F (Air/Fuel) ratio and the OBD-II protocol does not have a hook for the ScanGauge II’s computer to switch between the std. ~ 14.7:1 A/F ratio most everything else uses vs. the Lean-burn capable Honda’s while running in their 22.7:1 high FE A/F ratios. Since the ScanGauge II uses air flow to calculate fuel consumption, you can see how a Honda with a Lean-burn ICE’s i and aFCD’s are in no way accurate for those engines.

The last issue is a bit more serious but not a deal breaker by any means. Having to swap back and forth between your 4 Digital Gauges and the Trip Computers Current aFCD can be very inconvenient. If only there was a way to see 6 parameters including some of those in the Trip Computer section (aFCD) at the same time. I have access to (2) ScanGauge II’s and am tempted to piggy back one to the other given the (2) input data ports a ScanGauge II includes to see if I could actually view the aFCD on one while viewing the std. iFCD, LOAD, TPS, and VOLT I usually view on the other. I will let you know about this possibility in a later update.

Final Thoughts

The ScanGauge II at $169.95 shipped is not only an attractive addition vs. its predecessor but includes data points that are not available from anything else other then possibly a Hardwired SuperMid. For an off the shelf, all-in-one device to be able to plug-in, read a quasi-standardized data stream and calculate instantaneous FE while accumulating data so as to give a relatively accurate FE over a whole tank is amazing. Many of us have been waiting patiently for the as yet to be released Data Recording function for further “Out of the car - PC based analysis” but as of this writing, Ron DeLong of Liner Logic is waiting to update our ScanGauge’s with the new tools at HF2007

With 2 + seasons of experience in the Accord, I now know the ScanGauge II is giving me accurate readouts within .5 mpg over a current segment (not including my own forced 2 mpg offset) or a 1,000 + mile tank. Not only is the feedback allowing a very nice increase in FE, it saves enough at the pump to pay for itself in short order. Some might say yeah but yours was a review unit. Let me add that yes, this was a review unit for the sole purpose of wringing it out for all it was worth. I can also state I have purchased a total of (3) ScanGauge’s since I received the review unit. Those out of pocket purchases should give you an idea as to how much I believe in the product even with the few negatives posted above. Remember too that the ScanGauge II has even more features then those discussed above. I not only endorse the ScanGauge II as a great addition to any non-hybrid and many a hybrid driver’s tool box, I now own a few myself. Saying so should tell you all you need to know …



Good Luck

Wayne