Fuel composition PID

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  • Matt
    Senior Member
    • Dec 2008
    • 328

    Fuel composition PID

    I currently have 2013 Silverado 2500HD with a 6.0L in the shop having extend crank/cold-start run rough symptoms. No DTCs current or history in any module. This thing has 17,000 on it is all. First thing I wanted to check with my Verus is the alcohol content PID, (this is an E85 compatible rig). I can't find any fuel content PID data at all with my scan tool, or the ability to reset the fuel composition in the functional tests. I guess my question is there even a fuel content sensor on this vehicle? I just assumed there was due to its E85 gas cap. Any ideas
    P.S. Im running 18.4 in my EDGE, wouldn't think scan tool coverage issue
  • Witsend
    Banned
    • Nov 2012
    • 2942

    #2
    With only 17000 miles on a 6 year old vehicle that sits a lot, maybe the fuel has just gone stale or rodents have taken up a large residence in the air cleaner box. What codes you pull ? What is the fuel pressure?, Baro pid?, Long and Short Fuel Trims ? Grams per minute with MAF at idle would be useful info.

    Comment

    • Glide
      Senior Member
      • Jan 2015
      • 303

      #3
      Originally posted by Matt
      I currently have 2013 Silverado 2500HD with a 6.0L in the shop having extend crank/cold-start run rough symptoms. No DTCs current or history in any module. This thing has 17,000 on it is all. First thing I wanted to check with my Verus is the alcohol content PID, (this is an E85 compatible rig). I can't find any fuel content PID data at all with my scan tool, or the ability to reset the fuel composition in the functional tests. I guess my question is there even a fuel content sensor on this vehicle? I just assumed there was due to its E85 gas cap. Any ideas
      P.S. Im running 18.4 in my EDGE, wouldn't think scan tool coverage issue
      Looking at scan tool diagnostics for this vehicle in service information, there is no fuel content PID listed,and the only output controls are fuel pressure,fuel pump on/off,and fuel trim reset.
      It's not your Edge,it wouldn't matter what tool you have.

      Comment

      • Matt
        Senior Member
        • Dec 2008
        • 328

        #4
        Thank you Wit & Glide. Ill chase this thing with good old fashioned diag. I was just looking for a short-cut. Ill post results when I get them.

        Comment

        • bestdamgarage
          Member
          • Apr 2016
          • 99

          #5
          I had a older g6 needed to reset alcohol content and relearn it had to use tech 2 verus wouldnt do it.

          Comment

          • Matt
            Senior Member
            • Dec 2008
            • 328

            #6
            Originally posted by bestdamgarage
            I had a older g6 needed to reset alcohol content and relearn it had to use tech 2 verus wouldnt do it.
            That's kind of what I was wondering. This thing acts like classic alcohol content is off. I've reset several GMs in the past and puts them right-as-rain. I thought that's where I was headed with this Silverado and don't have the option.

            Comment

            • bestdamgarage
              Member
              • Apr 2016
              • 99

              #7
              Yeah the one i had said it was like 54 percent alchol which was way of the aclohol pid was displayed on the verus though..

              Comment

              • SnapOnKid
                Senior Member
                • Jan 2011
                • 884

                #8
                I believe these use a Virtual Flex fuel table which is based on 02 Sensor Feedback. Dependent on how rich or lean its burning it can calculate the alcohol content in the fuel based off a table within the calibration file. It uses that table to adjust the required fueling conditions.

                Comment

                • Matt
                  Senior Member
                  • Dec 2008
                  • 328

                  #9
                  Originally posted by SnapOnKid
                  I believe these use a Virtual Flex fuel table which is based on 02 Sensor Feedback. Dependent on how rich or lean its burning it can calculate the alcohol content in the fuel based off a table within the calibration file. It uses that table to adjust the required fueling conditions.
                  Well, that proves it. Once I get familiar with something they have to go and change it.

                  Comment

                  • SnapOnKid
                    Senior Member
                    • Jan 2011
                    • 884

                    #10
                    Originally posted by Matt
                    Well, that proves it. Once I get familiar with something they have to go and change it.
                    Here is a few images of a 2012 calibration with Flex fuel using 3rd party software that shows some of the tables.

                    When you get down to what it's doing and how it's doing it, it's pretty amazing.

                    None of the aftermarket 3rd party software companies support all the tables the OEM uses. We are actually lucky we get to see and adjust what we do have access to for offroad and performance industry.
                    Attached Files

                    Comment

                    • Dr Dave
                      Member
                      • Nov 2010
                      • 51

                      #11
                      so can i reset this

                      can it be reset with a old version tech 2 ? can my new zues reset it ? can a battery voodoo reset it ?Or all these tens of thousand dollars of equiptment I still need to go to the dealership?

                      Comment

                      • Steve6911
                        Moderator
                        • Feb 2007
                        • 2206

                        #12
                        Originally posted by Dr Dave
                        can it be reset with a old version tech 2 ? can my new zues reset it ? can a battery voodoo reset it ?Or all these tens of thousand dollars of equiptment I still need to go to the dealership?

                        See Snapon Kids first post in this thread. Some vehicles it can be set, other use the O2 sensor readings right after fuel up so it is a virtual reading and has no reset.


                        Copy and paste of service information


                        E85 Flex Fuel Description

                        E85 compatible vehicles no longer use an alcohol sensor to determine and adjust for the alcohol content of the fuel in the tank. Instead, the vehicle calculates the alcohol content of the fuel through measured adjustments.

                        The ethanol calculation occurs with the engine running after a refueling event has been detected via a measured change in the fuel level sender output. The virtual flex fuel sensor (V-FFS) algorithm temporarily closes the canister purge valve for a few seconds and monitors information from the closed loop fuel trim system to calculate the ethanol content. This logic executes several times until the ethanol calculation is deemed to be stable. This may take several minutes under low fuel flow conditions such as idle, or a shorter time during higher fuel flow, off-idle conditions.

                        Air-fuel ratios and the corresponding ethanol percentage are updated following each purge-off sequence. The fuel alcohol content percentage value can be read on a scan tool.

                        When an E85 compatible vehicle is built, an ECM or PCM replaced, or if the learned alcohol content has been reset with a scan tool the fuel system will need to contain ASTM gasoline with 10 percent or less ethanol content.

                        A minimum of 11 liters (3 gallons) must be put in the tank in order for the vehicle to recognize a re-fueling event. It is not necessary to turn the ignition OFF in order to have the re-fueling event recognized, however local safety regulations should be followed.

                        After the re-fueling event, the system registers the amount of fuel that was added, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines if the fuel added was either ASTM Gasoline or ASTM E85. Based on that determination, the system adjusts to the expected alcohol mix in the fuel tank, and then the fuel trim and O2 sensor activity fine tunes the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or E85 to gasoline, can result in driveability symptoms due to the inability of the system to adjust for fuel composition by not attaining closed loop operation.
                        Last edited by Steve6911; 02-15-2019, 07:09 AM.

                        Comment

                        • Witsend
                          Banned
                          • Nov 2012
                          • 2942

                          #13
                          so can i reset this
                          can it be reset with a old version tech 2 ? can my new zues reset it ? can a battery voodoo reset it ?Or all these tens of thousand dollars of equiptment I still need to go to the dealership?
                          Reply With Quote
                          Maybe during the relearn time the GM truck is trying to learn the fuel alcohol content, but it has another some other issue like some of the AFM lifters are sluggish and not coming back up in a timely matter and skewing results.
                          Who in their right mind other than a Corn Farmers, or Doomsday Preppers are putting E85 in their trucks these days, Lol.
                          If it were my truck , I think I would change the oil and filter with a good 5W-30 synthetic , clean the oil pressure sensor screen , the throttle body with WD40 on a rag, Reset KAM, and Plug in an AFM disabler before one of my AFM lifters collapse for good.

                          Comment

                          • SnapOnKid
                            Senior Member
                            • Jan 2011
                            • 884

                            #14
                            Originally posted by Witsend
                            Maybe during the relearn time the GM truck is trying to learn the fuel alcohol content, but it has another some other issue like some of the AFM lifters are sluggish and not coming back up in a timely matter and skewing results.
                            Who in their right mind other than a Corn Farmers, or Doomsday Preppers are putting E85 in their trucks these days, Lol.
                            If it were my truck , I think I would change the oil and filter with a good 5W-30 synthetic , clean the oil pressure sensor screen , the throttle body with WD40 on a rag, Reset KAM, and Plug in an AFM disabler before one of my AFM lifters collapse for good.
                            E85 Is used in Racing as well. It's way cheaper than racing fuel.

                            E85 is around $2 a gallon where I live Vs. 10$ a gallon for 100 octane racing fuel.

                            It makes more power and runs cooler but its down fall is that you use more of it and get less MPG's.

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