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Thread: Flex Fuel M156

  1. #1
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    Flex Fuel M156

    Does anybody have any clue where to adjust the stoich ratio of 14.7 for gasoline to Flex Fuel? I can?t seem to find any parameters that allow to adjust for flex fuel. I know it has been done before. Please point me to the right parameters to make the corrections.

    Merry Christmas everybody!

  2. #2
    Senior Tuner BackyardTurbo_FTW's Avatar
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    They sell flex controllers to add on but I really prefer to NOT use them and just make a custom tune for E85 (or whatever blend you are running)

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    I don?t plan on running the controller. I ran it before but car was unhappy adjusting to it. My plan is to have a custom tune but I was having trouble scaling the injectors last time. Also, any pointers on which parameters to adjust for E85? Advancing timing would be one what about lambda? 14.7 for stoich and 9.8 for E85 blend. How do I make that adjustment?

  4. #4
    Senior Tuner BackyardTurbo_FTW's Avatar
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    Leave stoich, there's no need to change that. Adjust the injector multiplier by the amount the LTFT is. Then work on the load tables to keep it from tripping limp mode

  5. #5
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    Quote Originally Posted by BackyardTurbo_FTW View Post
    Leave stoich, there's no need to change that. Adjust the injector multiplier by the amount the LTFT is. Then work on the load tables to keep it from tripping limp mode
    Just to ensure I got the steps correct:

    1) log LTFT at idle and driving around with stock injectors
    2) change to larger injectors
    3) log larger injector at idle
    4) adjust injector multiplier table to match stock injector LTFT percentage
    5) adjust load tables to prevent limp
    6) repeat 4&5 until finalized

    Once LTFT is tuned and car does not go into limo mode. I can then start to advance timing slowly.

    Correct me if I missed anything.

  6. #6
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    Do I simply adjust MAF when running E85?

  7. #7
    Senior Tuner BackyardTurbo_FTW's Avatar
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    I would install the injectors and put E in the tank if thats what you plan to run. Then drive it around easy a bit until the LTFT settles. Whatever that % is, adjust the injector multiplier by that amount. If the LTFT is within a couple percent after that, finish fine tuning trims with MAF scaling. Then work on load/timing etc after that.

  8. #8
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    Thanks! I?ll give it a go

  9. #9
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    What are the capabilities of the OEM fuel system on ethanol? E47? Full E85?

  10. #10
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    Quote Originally Posted by RYRO View Post
    What are the capabilities of the OEM fuel system on ethanol? E47? Full E85?
    From research, there are many full E85 with stock system out there without any known issues.

  11. #11
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    Quote Originally Posted by BackyardTurbo_FTW View Post
    I would install the injectors and put E in the tank if thats what you plan to run. Then drive it around easy a bit until the LTFT settles. Whatever that % is, adjust the injector multiplier by that amount. If the LTFT is within a couple percent after that, finish fine tuning trims with MAF scaling. Then work on load/timing etc after that.
    I tried everything mentioned above and the first night (53 degrees), car ran fine without adjusting too much parameters. Car didn?t limp nor throw CEL. Today, I drove it as it was and CEL keep coming on; displaying cylinder 1 misfiring. Also, I notice when CEL turns on, my commanded AFR becomes 20+. I tried all sort of load table, inject table, and timing but the misfiring keep showing up.

    Would you know what may cause that? Why only cylinder 1 and not other cylinders. I also noticed when car was running smoothly last night, my commander AFR was at almost 14 rather than my existing 12.5. I didn?t adjust anything, just running different fuel. Would the fuel make correction to my commander AFR?

    Any help would be great.

  12. #12
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    Quote Originally Posted by Fu03steveC63 View Post
    I tried everything mentioned above and the first night (53 degrees), car ran fine without adjusting too much parameters. Car didn?t limp nor throw CEL. Today, I drove it as it was and CEL keep coming on; displaying cylinder 1 misfiring. Also, I notice when CEL turns on, my commanded AFR becomes 20+. I tried all sort of load table, inject table, and timing but the misfiring keep showing up.

    Would you know what may cause that? Why only cylinder 1 and not other cylinders. I also noticed when car was running smoothly last night, my commander AFR was at almost 14 rather than my existing 12.5. I didn?t adjust anything, just running different fuel. Would the fuel make correction to my commander AFR?

    Any help would be great.
    So I checked cylinder 1 spark plug and it was fine but I changed it just to be sure. It was still throwing CEL for cylinder 1 misfiring and random cylinder misfire. I dug a bit more and here are the results:

    - Left injector multiplier alone, vehicle at idle will not display STFT percent and within 30 second, engine will start knocking and throw Cylinder 1 misfire code. AFR at idle reads close to 14.7 at both o2 sensors.

    - Increased the entire injector multiplier table by 15% from factory ECU setting. Engine idles fine throughout entire temperature range from cold to warm; no CEL. STFT was changing between -20 and -25 percent.

    My question is: is it normal for STFT AND LTFT to be around -25 when running flex fuel? My goal is to run E85 but currently sensor is reading E58. Seems like the richness of the fuel equates to flex fuel needing roughly 30% more than gasoline. Anybody with experience with this?

    Thank you,

    SF

  13. #13
    Senior Tuner BackyardTurbo_FTW's Avatar
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    Can you post the tune and log?

  14. #14
    without a flex fuel sensor, the ECU compensation will never be fully correct. scaling for fuel will be much different between fuel of gasoline to alcohol.

    the ECU does manage all adjustments through lambda values and lambda between all fuels are the same (air fuel will be different between fuels but lambda is the same. ECU only cares about lambda). the differentiating factor is that -3 fuel adjustment on gasoline versus ethanol should see a 25% increase in flow. -3 wouldn't really be -3 from gasoline to ethanol.

    as far as the fuel system, there are no issues with ethanol and can be run to full e85/85% ethanol without issue.

    MIV2 Pro will allow input of external sensors, but HPTuners has not developed mapping for flex fuel sensors through use of external sensor input. It is possible but has not been developed.

    ethanol is very forgiving in the fact that it will mask issues with a tune. where you would normally see a misfire, ethanol won't misfire but should.

    post your logs and map. would need to see both to identify what is being referenced and if it is correct for what you're trying to achieve.
    Last edited by hachiroku; 4 Weeks Ago at 03:56 PM.

  15. #15
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    4th WOT v10.6.hpl
    4th WOT v10.6 stage 1 nos.hpl
    HOPE E85 V10.6.hpt

    I have spend few mornings dialing the ECU in. See attach log and tune. I have a few question from here as I have gotten the car to run decently with a few small problem:

    1) At cold engine temp, cold start will throw CEL displaying cylinder misfire. Possibly not enough fuel, where can I make adjustment to add more fuel? After engine oil reach 100 degrees F, I can clear CEL then restart the car normally.

    2) Both logs are WOT in manual mode at 4th gear. I targeted 0.88 lambda (13.0 AFR) at WOT but why is my commanded AFR shifting to lean then rich (on one log) and another simply became enriched at targeted AFR. I'm not seeing changing elsewhere which may cause this.

    Let me know what you guys see which I can improve on.

    Thank you,

    SF

  16. #16
    what injectors do you have?

  17. #17
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    Quote Originally Posted by hachiroku View Post
    what injectors do you have?
    Bosch 630cc injector

  18. #18
    couple of things...

    1) i need a cold start data log with misfires logged
    2) need your base map without changes. yours differs from my E63 map in some regions which i don't think you modified
    3) you cannot alter Lambda as this is mapped on maps we do not have access to with current build of HPTuners
    4) with your datalog update your channels with every single channel available. i don't see misfire counter or knock retard per cylinder. this will help to determine if its a mechanical reason like air leak or actual tune.
    5) what year and model is your car

    will need those listed items before i could identify your misfire issue. from your logs seems like your car is running pretty solid.
    Last edited by hachiroku; 3 Weeks Ago at 12:02 AM.