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Thread: E85 FlexFuel Conversion, 2012 Chevy Volt, 2012 Cruze Eco

  1. #1
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    E85 FlexFuel Conversion, 2012 Chevy Volt, 2012 Cruze Eco

    Right now I'm trying to decide between EFILive and HP Tuners.

    Specifically, to do this conversion below on my 2012 Chevy Volt/s.

    https://forum.efilive.com/showthread...uel-Conversion

    Apparently, the Volt uses the same GM Part number for the ECM as the Cruze ECO.

    A major deciding factor for me to go HP Tuners is if these same Flex Fuel Parameters are available to be edited in VCM Suite, as they appear to be with the Cruze ECO using EFI Live?

    {B0178} Flex Fuel Option
    {B0184} Flex Fuel Sensor Type
    {B0189} Detect Ethanol Change
    {B0187} Ethanol Change Delay
    {B0188} Ethanol Change Amount
    {B0186} Flex Fuel Sensor Diagnostic

    Has anyone seen these parameters as being available to be edited using HP Tuners on a Volt or the Cruze ECO?

    Thanks

  2. #2
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    Could you help me understand why you would want a volt running E85?

    I understand the cruze, it's a turbocharged engine and you add boost, advance timing, etc (i assume). But the volt is a naturally aspired engine, why would you want to use a less energy dense fuel? do you plan on upping compression or turbocharging your volt?

  3. #3
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    E85 currently is 35% cheaper than 91+ in my area, so this should save me about 15% at the pump.

    Plus it is one just one small step closer to running my own E100 (moonshine). Perfect for when the Zombie Apocalypse breaks out. Assuming the E100 isn't consumed by other "needs", like umm, trade.

  4. #4
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    2012 Ecosensor diag.JPGFlex fuel.JPG

    Good Luck!

  5. #5
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    It won't save you money at the pump because e85 will get far less miles to the gallon. You'll just burn through it quicker and be at the pump more often.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  6. #6
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    Perfect thanks for the screenshots Cruze, that's exactly what I needed to see.

  7. #7
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    Sensor installed but wont stay running with Sensor enabled.

    Using beta 2.25.1096, as only the most recent few releases support my application.

    1. The car still has the same pump gas in it with all of my testing. When I flash back to the stock tune the engine runs normally.

    2. The sensor when enabled in the ECM displays roughly 8% alcohol, which is typical of pump gas in this area.

    The problem however is that after the engine starts and runs for approximately 10-15seconds the following DTCs are displayed.
    P0AB9 Hybrid System Performance
    P0AC4 Hybrid Powertrain Requested MIL Illumination

    Once these DTCs are set the engine stalls or more likely is killed.
    The car enters "Propulsion reduction mode" and the engine is then no longer available.

    The first test I tried was to simply enable the Flex Fuel Sensor which I installed. Simply doing this caused the engine to run rough, and eventually the above DTCs get set.

    The second test I tried was to try to set every alcohol table and setting to the same values as the GAS values. Only as a means to try to keep the engine DTCs from faulting out and stalling the engine. When I did this I noticed that the engine ran smoother, but the Calculated engine load never went above 10%, where normally its 70-100% before faulting out.

    I'm not sure why the engine runs fine with the sensor disabled, but enabled with everything set to gas settings its not able to keep going.
    Last edited by MrComment; 10-19-2014 at 02:10 PM.

  8. #8
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    Next test, Fuel Injector Swap.

    Injector_Flow_Values.JPG

    Assuming I can ever figure out the previous issue.

    In the meantime I'm going to swap out my stock Volt injectors with the stock Cruze injectors. Hopefully this should be a copy and paste correction to the injector tables, and then I should have more than enough headroom to play with for E85. Maybe the extra slop in injector size might make it run better with the content sensor enabled?

  9. #9
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    Depending on where you installed you the sensor, did you greatly reduce you delay volume? If your using cruze injectors you should be able to copy the data straight out of the cruze

  10. #10
    How much fuel do you consume in your volt? The volt owners I know run less than 100 gallons a year, most are less than 20 gallons a year. How will the special pressurized fuel tank of the volt handle the evap of E85/E100?

  11. #11
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    Installed location of the sensor.

    The sensor was installed as close as I could get to the fuel rail.

    The initial values used were 0.1L for the delay and transition but its obviously even less than this.

    For now Ive decided to just to try to run it on dedicated E85 with the Cruze injectors, because with the flex sensor enabled it wont run even on pump gas for more than 10-15seconds.

    Last night, I directly copied all of the Injector Control values and General Fuel System values from the stock 2013 1.4L Turbo Cruze Auto tune, and installed the new injectors.

    So far the engine starts right up and seems to run without issue (with E8 pump gas). At warm idle and 30% calculated engine load these injectors are only on for just slightly over 1ms. Though the ecu hasn't complained yet, I don't think I would want to run any larger injector than these. Even though normally the engine sees a lot higher load than this, in service mode with the hood up and HV battery above 45% it doesn't seem to keep charging after a few minutes. More or less "normal" operation for the volt.

    Certainly plenty of injector head room for this NA application. Assuming I don't get stranded in the next couple of days. Maybe this weekend, I'll run the gas out of tank, and put some ethanol in and see if I can rescale the injectors to run only E85 without the sensor for now.
    Attached Images Attached Images

  12. #12
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    Running on E60 now, will be up to E70 on the next fillup.

    After a few days of running around on E60 I'm pretty confident that the "visible" values given in the stock Volt tune file are legitimate numbers for E85.

    Adjusting all of the GAS table values manually given the stock alcohol data and multipliers seems to produce good results. At least with testing on my daily commute, not sure about extreme stress cases such as WOT, as I cant command these directly on the Volt, but the car charges normally in EV extend and Mountain without any trouble codes, knock or unexpected Long Term Fuel Trim deviations. The CAT Temperature appears to be operating within acceptable values as well.

    Therefore, the issue with the sensor not working is almost assuredly due to missing data in a table that is not visible with HP Tuners.

    Also if these tables were visible then the values should be a simple copy and paste from the given gas tables, as the car seems to do it's thing fine on alcohol.

    I also swapped around the Normal and Sport driving modes, so that the default pedal input is Sport at start up and Sport even while in Mountain Mode. Of course I live in Indiana so I don't really have to deal with real "Mountains" but I do use mountain in a Hold mode fashion, at least until I can figure out how to flash the whole car to 2013+ programming.

    For those interested I posted my changes below.

    Changes to the Stock 2012 Volt tune, include:

    Revision 1: (Ensure ECM can be tuned, makes sure I have enough Injector headroom)
    Copy and Pasted all Injector Control Values from Stock 1.4L Turbo 2013 Cruze Auto tune, as well as all Fuel System General Specifications.
    Obviously, this tune requires that the Stock Chevy Cruze injectors be swapped into the Volt.
    Completed and Tested on 10-21-14, runs ok on Gasoline E8

    Revision 2: (Check to see if hidden OEM tune's torque control limits will accept real E85 outputs from the engine by changing a minimum number of exposed variables.)
    Re-scaled the injector flow rate by 75% ("Flow Rate vs Press" X 0.75) for a rough E85 tune, thereby injecting 25% more fuel than stock.
    Completed and Tested on 10-22-14, runs ok on E60, i.e. with 0.6gallons of gasoline left in tank, filled 8.7gallons of E70 (winter E85). (Coldest outdoor temp tested 46deg F)

    Revision 3: (Update the rest of the OEM tune based on exposed FlexFuel variables and desired Alcohol composition.)
    Note1: Manually calculated for (E70) fuel composition from the OEM tune file.
    Note2: Im not sure if all of these parameters with actually be taken into consideration with the FlexFuel Sensor disabled.. (Do not enable sensor, engine will not run correctly!!!)
    Airflow:
    Airflow Speed Density - set all parameters to 0.979
    Fuel:
    Fuel Density - 768,350
    Cranking Eq Ratio - Blended via Excel File based on Stock values
    Open Loop Gas (Gear) and Gas (P/N) - Blended via Excel File based on Stock values
    IVT Gain A - Replaced with values from IVT Gain D table, per values given in IVT Gain Zones for 70% alochol.
    IVT Gain CLO Gas - Replaced with IVT Gain CLO Alc (probably not used anyway as CLO tables are disabled)
    Spark:
    High Octane Table - Blended via Excel File based on Stock values from Flex Fuel Spark and Flex Fuel Mult
    Low Octane Table - Blended via Excel File based on Stock values from Flex Fuel Spark and Flex Fuel Mult
    Cranking Table - Increased by +4 per Alcohol adder table values in the OEM tune.
    Torque Management:
    Replaced all Torque Coefficients Gas tables with given OEM E85 tables.
    Completed and Tested on 10-24-14. runs ok on E60

    Revision 4: Make Sport mode the default pedal setting
    Note1: Obviously, It will not display as such on the Instrument panel!
    Swapped Map A - Normal, with Map C - Sport/Tow/Eco, in order to make "Sport" Mode the default drive mode. Sport mode is now "Normal".
    Completed and Tested on 10-25-14, not a requirement for E85.

    Revision 5: Replaced "Winter" driving mode with OEM Sport Settings.
    Winter Mode = Mountain Mode in the Volt.
    Completed and Tested on 10-25-14, not a requirement for E85.

    Revision 6: Slight Fuel Injector Rescale correction.
    Multiplier is now (0.754219) based on the given Stoich AFR for E70 in the Stock Volt tune file.
    This should in effect target an 11.07207 AFR.
    Attached Files Attached Files
    Last edited by MrComment; 10-26-2014 at 03:31 PM.

  13. #13
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    Mileage Results etc...

    Based on the mostly Gasoline data I have collected over the last couple of months I decided it was time to start compiling my paper notes into an excel spreadsheet, this way I can see how big of a loss in gas mileage I'm going see with the above ethanol tune. This is important, as with winter approaching EV miles are going to decline further with the electric heater blasting, resulting in more alcohol being consumed. Typical daily commutes are over 100miles for car 1 and 50miles for car 2.

    There is significant variation in EV extend miles and some odd flyers within the data. Green and Blue are two different Chevy Volt/s, as my wife and I have different charging opportunities and daily commutes. Red points are based on my E70 tune with E60 in the tank, looks like its going to take a few more weeks to burn out the rest of the E60 so I can fill it up the rest of the way with a clean tank of E70(E85).

    Some of the lower gas mpg numbers i suspect are related to some "Mountain Mode experimenting", but thanks to GE never charging either car while under their stewardship, I know that either car's lifetime mileage solely on gas is actually 33.4mpg. It's otherwise pretty dicey trying to extract exact fuel usage and miles driven associated with the engine being "on", so for that I'm just going to have to trust GM's indicators and hope it makes some more sense after I get more data points.

    Update 11-1-14: While I was reviewing my data I discovered a calculation error. The data for fuel consumed is currently not reporting accurately, since I rescaled the injectors with my dedicated E70 tune. This became obvious when the 9.3gal tank got to 50% full, but the total fuel consumed was only 3.5gals on the odometer. So I still need to update my graph below by basically adding 25% to the gals used for each E60/E70 data point.
    Attached Images Attached Images
    Last edited by MrComment; 11-01-2014 at 02:39 PM. Reason: calculation error

  14. #14
    Laz and I ran E85 all summer and never saw higher than an 80% injector duty cycle, even when hitting the rev-limiter so Cruze injectors don't seem to be a necessity.

  15. #15
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    Agreed, last week I swapped back to the stock volt injectors.

    It might also be worth pointing out on in this thread we did finally figure out how to enable the sensor to utilize the ECUs flex fuel support also.

  16. #16
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    MrComment,

    You are a legend, one of my annoyances with this car was having to switch it to performance mode every time I got in the car, after following your post on the using Map C for Map A and B, the car is much better to drive, do you have any advice on what I can play with to improve the fuel economy of the petrol engine, I'm sure we can get better fuel range out it.

  17. #17
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    Honestly after taking a long break from trying any tuning at all. I just sort of got talked into tuning this thing again.

    Laz is really the mpg guru when it comes to mileage, I believe he's typically getting around 40mpg.

    From my experience though, I've been working on "fixing" bugs that I noticed after stumbling onto the alcohol content sensor solution. Namely all of my airflow settings seemed to require at least a -4% recalibration after enabling the content sensor, but oddly not all together linearly. I'm pretty sure I just wasn't paying close enough attention before I started messing around with the tune again, but as such I haven't ventured far from the stock tune path just yet. I'm still just trying to trying to confirm the basic stuff is tuned right from the factory first.

  18. #18
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    To anyone reading this that might care about enabling the Alcohol Content sensor on the Volt.

    The magic trick was swapping all of the default Gas Torque Management tables into the E85 tables. Oddly the stock E85 values can also be swapped into the Gas Torque Manage tables and this will also work. Basically the two sets of tables apparently just need to match but they don't appear to blend properly. Perhaps a later more dialed in tune may improve the blending in TM, but this is what it takes to initially get the engine to stay running with the content sensor enabled.

    After the above is set the rest of the blending in the ECU appears to work as would be expected, which lets the car run as a Flex Fuel car, but apparently the entire tune needs to be reviewed and setup from scratch.

    Currently, a work in progress.
    Last edited by MrComment; 12-05-2016 at 04:54 PM.

  19. #19
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    2012 volt frank 220 OEM.hpt

    hi mr Comment
    i have a 2012 chevy volt , but with the difference , its a euro version , we have 4 drive modes 1 normal 2 sport 3 mountain 4 hold , i will include my stock file , so you can see there are some differences , i hope you like it , it can be interesting /useful 4 u , over here we also have different fuel , 95/98 oct of gas
    you will see some thing are different from us version

  20. #20
    I'm sure Laz would be interested in seeing your tune.

    At this point all 3 of us (MrComment, Laz and I) are running E70 with most of the E10 portion finished, with updated VE, Map and injector changes from MrComment. Last I heard tho MC wants to redo his VE.

    We found all kinds of things wrong with the Volt tune that were much better in the Cruze so MC & Laz have adopted (stolen actually) much from the Cruze and even the 2012 Buick Regal 2.0T.

    Laz also managed 104 mph yesterday and 30 mpg with E70 and is planning to try 110. I gave up on speeds >100 mph ages ago when I had a '75 Pontiac TransAm. (My max was 145 mph.)

    FWIW, MC and I both have the ethanol sensor.

    Laz noticed that knock learn was disabled so the HO spark table was always used and it has a LOT of knock at cruise and above. He has since re-enabled knock learn.

    Fuelverine (Engimuneer) also noticed that the fueling relearn in most non-FFV GM vehicles is intentionally disabled with outrageous values that can never be reached. He's our 4th member, but is busy with personal things so won't be tuning with us until maybe next month at the soonest. Since he lives at a high altitude and Laz is at sea level where it's always warm and I live in the north where it gets cold, we have a wide range of testing conditions.
    Last edited by TownDrunk; 02-18-2017 at 07:24 PM.