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Decel Popping and Map Selection

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  • Decel Popping and Map Selection

    Hi All,

    motor: 400ci BPE 236/242 110 lobe10.3:1 comp. alum heads - 517hp 546ftlb

    pro flo 4. edelbrock sump kit

    Car has 350 miles on combo. I did ask it to relearn and that made no difference.

    My concern is the decel exhaust popping. i have looked for leaks and can find non. i assume the AFR would be bad everywhere if that was the case? could be wrong.

    The short and long FT are only super happy just off idle. and after that the long is maxed out

    The idle quality was great from first start and the unburn gas smell was not there. now that is there as well and it eye burning to be near the car when idling or driving.

    Can you look at the screen capture and offer advise. I guess i could change the decel figure up to 6000 and take care of the popping that way, but that seems like a bandaid.

    map is #5025 with the amount of ST/LT being so positive could it be the wrong map? Based on the sheet its the right one.

    9-12 hg at idle and that fuel pressure looks very unstable.

    and it will pop at any rpm off throttle. 1600 - 2200 seems the most consistent area.
    Last edited by Monkeysgarage; 08-17-2020, 02:40 PM.

  • #2
    Pete here are the additional video as requested.



    • #3


      • #4
        the fuel pressure doesn't look right it should be 58 or 43 depending on the map you are useing.less vacuum more fuel p.s.i decell little lower than set p.s.i .

        changing fuel decell setting have helped others with popping on decell.

        low fuel p.s.i will make e c u try and richen the system.


        • #5
          check the map you chose the 9 in of vacuum shows a large cam.


          • #6
            map is 5025 = 58psi - 381-405 rave 230 up cam and 12-5 hg.

            i got all that.

            the PSI is coming from edelbrock sump. they are preset to 58. so not sure why the unstable psi.

            i just went for drive and upped decel to 2000. didnt fix it.


            • #7
              sorry. cant get it to put multiple video in one message


              • #8
                last one.


                • #9
                  Peter called. Thanks mate! New map 5030 installed and a few other magical changes (no changes to decel, timing, and a bunch of other stuff), and right off the bat the throttle response is greatly improved. The FT's, both are instantly better, and I cant wait to get some miles under this tune this week. quick run around the block and no popping on decel.


                  • #10
                    I have the exact same engine. Different issues though. I think I will try the 5030 map too. Thanks for sharing. What other "magical changes did you make?