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Thread: sierra 2016 fuel flex activation

  1. #1
    Tuner in Training
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    Nov 2019
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    sierra 2016 fuel flex activation

    hi,
    (L83 engine 5.3 on sierra 2016)
    for activation of the fuel flex, I don't find full explain and it's my first use of hptuner, I need to find how to from forum, youtube... so I dit this and I would like to know if I am fine:
    -engine-fuel-fuel sensor: change "virtual" for "sensor"
    -engine diag-DTCs- P0178, P0179, P2269 : "activate" and "MIL on second error"
    -stoich AFR vs e85%: all are 14.10, change for:
    0=14.67822
    6.3=14.32227
    12.5=13.96582
    18.8=13.60938
    25=13.25244
    31.3=12.89648
    37.5=12.54053
    43.8=12.18359
    50=11.82764
    56.3=11.47119
    62.5=11.11426
    68.8=10.75781
    75=10.40186
    81.3=10.04590
    87.5=9.68896
    93.8=9.33252
    100=8.97656

    and min and max e85 ratio was 10 and 10, change 10 to 100%.

    put the alky sensor on the pin 38, (already wired, white wire, no stock alkysensor on the truck, it's a gas truck, cut it to put the sensor on it.)

    check on spark advance, look different on gas or e85, so I thinking it's already fine.

    after all of this, it work fine, show 74% of ethanol, stft near zero, a little +,

    so I would like to know why I have allready a wire on the pin 38, if min max is better 0 to 100% ? (let 10 because set to 10 is set for gas), and if I need other setting.

    thank you.
    Last edited by sierra15; 11-11-2019 at 02:30 PM.

  2. #2
    Tuning Addict 5FDP's Avatar
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    There is a flex fuel harness already under the truck on the frame, so that is why there is a wire into the computer already.

    I have my min/max settings at 0 and 85% with no issues.

    You also want to turn the diag test on in the fuel tab for the sensor. Past that you have the rest of it good. From there it's making the tune how you want it for running E85 fuel. Lots of other crap can be done to make it use the flex fuel feature better.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
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    ok,
    so I will search to turn on the sensor diag test.
    but what are the other crap?

    May be one other thing I can do is cold start, it' s not too good, may be I will find a "crank AFR table"?

  4. #4
    I'll defer to those with more experience but I think you are looking for a cranking EQ ratio Alcohol under the fuel tab. I'm starting to explore cold start on e85 and that's where I'm starting to tinker. The sensor diagnostic should be located under fuel system, diagnostics

  5. #5
    Tuning Addict 5FDP's Avatar
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    If it's cold outside, like really cold, it's always going to crank a while to get running. I was good down to about 30 degrees before it started taking extended cranks. Now I just stopped running it because I'd only be getting 6-8mpg with the cold instead of the 10-12 with regular pump 89. I only drive city so my mileage is always terrible.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  6. #6
    Tuner in Training
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    Nov 2019
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    yes, I will look for this cranking EQ.
    ya mileage is baddest, but here e85 is 0.50 to 0.60 euros/liter and gas is at least 1.5euros /liter, so until mileage is less than 3 more...

    this fuel flex system is not perfectly build, I am thinking than the better way for cold start is glow plug or heated injectors, imagine if you use E100, you will never start when cold, using 15% of gasoline only for cold start is not perfect, ( will you use 15% of gas into diesel instead of glow plug?)