Chrysler Misfire counter?

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  • SiN360
    Junior Member
    • Aug 2013
    • 1

    Chrysler Misfire counter?

    Hello,

    I have an 05 Dodge Durango with a 4.7 that I'm working on. I can feel it missing, but the codes where erased before I got to look at it. Under the misfire test
    "what cyclinder is mis-firing" the misfire monitor status was showing questions marks when it came in. I had a chance to look at it some more today and now it's showing suspend. I have all the cylinders showing 0 as if they are not missing. What is the monitor state supposed to be showing when it's working correctly I haven't used it on a Chrysler in a while.

    Thanks
  • Modis500
    Senior Member
    • Sep 2012
    • 358

    #2
    Do you have access to Mode 06 info that may tell you individual cylinder misfire count?
    "If you aim for nothing, you'll hit it every time!"
    Zig Ziglar

    Comment

    • Joe Rappa
      Snap-on DSD
      • Aug 2007
      • 2050

      #3
      When Dodge shows the "Which Cylinder is Misfiring" Test, misfires will count up just like a GM car will. If the engine is shaking and it is not showing a misfire, try to give it one to see if it shows up on the scanner. As dumb as that sounds, it will eliminate the possibility that there is an imbalance in the engine and not a misfire.

      Joe
      "You don't build a reputation on what you're going to do"
      Henry Ford

      Comment

      • Crusty
        Senior Member
        • Dec 2007
        • 2450

        #4
        Originally posted by SiN360
        Hello,

        I have an 05 Dodge Durango with a 4.7 that I'm working on. I can feel it missing, but the codes where erased before I got to look at it. Under the misfire test
        "what cyclinder is mis-firing" the misfire monitor status was showing questions marks when it came in. I had a chance to look at it some more today and now it's showing suspend. I have all the cylinders showing 0 as if they are not missing. What is the monitor state supposed to be showing when it's working correctly I haven't used it on a Chrysler in a while.

        Thanks
        Some misfire counters need the vehicle to be driven before they'll update.

        Some misfire counters won't register misfires if they are less than 8% of cylinder firings.

        Take a look in ODBII and see if there are any "Pending" codes.

        Even though misfires should be 1 trip codes, sometimes the ECM isn't ready to flag a code YET. It could show up on the next drive cycle.

        Don't forget that something that "feels" rough could be something like a motor mount grounding out.

        Also look at the emissions "Monitors" to see what monitors have "Completed" since the codes were cleared. Try to drive the vehicle to get as many monitors to make a decision and check for any other codes or pending codes.

        Comment

        • Skip
          Super Moderator
          • Apr 2008
          • 605

          #5
          When the codes were cleared the PCM lost its "Adaptive Numerator". That is the value it uses for miss fire moniotor. It is a snapshot of the ckp pattern on a fuel cut out decel that it can compare the running pattern to. As Crusty said, you will need to drive the car and perform 4-5 high speed coast downs before it will be relearned.

          Comment

          • Crusty
            Senior Member
            • Dec 2007
            • 2450

            #6
            THANKS for clarifying that SKIP. I had forgotten about the DECEL requirement for Chrysler to update.

            FORD also needs some long hard decels to update the BARO sensor (if I remember correctly)

            Comment

            • Orevin
              Senior Member
              • Aug 2010
              • 1110

              #7
              Originally posted by Crusty
              THANKS for clarifying that SKIP. I had forgotten about the DECEL requirement for Chrysler to update.

              FORD also needs some long hard decels to update the BARO sensor (if I remember correctly)


              The BARO pid on older Ford is calculated (no sensor) under driving conditions with "high throttle openings". Vehicles with an ESM update the BARO reading when the key is turned on and can also adjust BARO "on the fly", using MAF and MAP under certain conditions.

              The misfire profile is learned on deceleration from above 60 mph to around 40 mph.
              -Kai-
              Chicago, IL

              Comment

              • Crusty
                Senior Member
                • Dec 2007
                • 2450

                #8
                YUP, You're right. Again I had forgotten about the WOT loads to update the BARO...

                I seem to remember having to do that with a 2005 F-150....if you consider that an "older Ford"...LOL....for me an older Ford is a 1968 Cobra Mustang but who's counting the years...LOL

                THANKS for you USUAL EXCELLENT input OREVIN-!

                I wonder if the original poster is looking in-???

                Comment

                • saulc1981
                  Junior Member
                  • Jun 2019
                  • 6

                  #9
                  same issue

                  Im working on a 04 5.7 ram and cant for the life of me get those misfire counters to go past 0 even if i create a misfire. Taked to snap today and he told me that if the misfire was really bad that the scanner wouldnt be able to pick it up but then i read on here where if it isnt bad enough it wont register it. Ive done numerous decel already too and driven miles on it and nothing still.

                  Comment

                  • Skip
                    Super Moderator
                    • Apr 2008
                    • 605

                    #10
                    A couple things may be going on. Depending on how you set the miss, it may ignore it. If you set a DTC by disconnecting an injector or coil, the PCM won't bother setting a miss fire code. You can also check the OBD II monitor status to see if the miss fire monitor is enabled.

                    Comment

                    • greasybob
                      Senior Member
                      • May 2008
                      • 1590

                      #11
                      Are you looking at misfires in the systems test "which cylinder is misfiring" ? Or just in the general data list ? You could try to check the mode 6 monitor systems tests $A2 through $A9 in the General Functions.

                      Comment

                      • saulc1981
                        Junior Member
                        • Jun 2019
                        • 6

                        #12
                        Originally posted by greasybob
                        Are you looking at misfires in the systems test "which cylinder is misfiring" ? Or just in the general data list ? You could try to check the mode 6 monitor systems tests $A2 through $A9 in the General Functions.
                        I was under the system test misfire monitor. I also took a look at the mode 6 data and it does not show any misfires it does show TID $58 TID$59 TID$5A TID $72 all failed. But doesnt show me defifnitions for them.

                        Comment

                        • PLohr
                          Junior Member
                          • Jun 2018
                          • 15

                          #13
                          I'm having trouble getting misfire information as well. The vehicle is a 2008 GMC Yukon XL. It is clearly misfiring during cold starts. I am using EFI Live as a scan tool. All 8 misfire counters always have zeroes. I've logged these in several separate sessions, they always contain zeroes.

                          Even though I'm not using a Snap-on scanner, I posted this because perhaps the ECM waits for certain parameters to be met before misfires are logged.

                          If you are interested, using the link below you can see the post I made on the EFI Live forum about this issue. Still hoping for a response on that forum.


                          https://forum.efilive.com/showthread.php?29897-misfire-logging

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