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Thread: Odd values with RAFIG for B4307 base airflow

  1. #11
    Lifetime Member
    Join Date
    Aug 2013


    +1 what joecar said about cleaning the MAF sensor.

    The only airflow PIDs I need are MAF Frequency and MAF airflow.... so I'd say keep the CALC.VET PIDs and drop the RAFIG PIDS.

  2. #12
    Senior Member
    Join Date
    Aug 2016


    I cleaned the MAF, did a RAFIG log and updated B4307 then went on a trip from Indy to the Tail of the Dragon with a group of friends. I got 3 logs on I-74, and like a dummy forgot to log GM.VOLTS. These logs wanted to increase B5001 and B0101, nothing crazy though. The logs are below:

    Logs without GM.VOLTS, with cleaned MAF and updated B4307:
    GTO Oct 19 2018 Highway 74 log 3.efi
    GTO Oct 19 2018 Highway74 log 2.efi
    GTO Oct 19 2018 Highway74 log 1.efi

    When I got to our cabin, I updated the tune with this data, and of course my wideband decided to start giving wonky numbers. I have an analog Speedhut AFR gauge hooked up to my LC-2, and it was acting very erratically. Finally yesterday I recalibrated the wideband sensor and went for a drive. This time I got some good data with GM.VOLTS.

    It looks like voltage dropped from 14.0-14.1 to 13.6-13.8 when the vehicle was stopped, you can see this at frame 23,847 and again at 24,394. This tune and log are below:

    Updated tune and log with GM.VOLTS:
    GTO Oct 28 2018 drive to Brown County.efi

    Data for B0101 and B5001 didn't look too bad. Volts stayed between 13.6 and 14.1V, which seems fine to me. To be transparent, I have never logged volts before, so I can't say much to its effects. This log started on the highway, then had a little in-town driving.

    Overall there is the occasional bucking at very low TPS or off throttle, but it seems to be happening less often and when it does it is less severe.

    I spent some time in heavy bumper to bumper traffic which SUCKED, but it gave me time to think about why my idle kept swinging wildly after I'd move a few feet using mostly only the clutch. I updated my spark underspeed and overspeed error tables to reduce their effects, and that got rid of almost all my idle swinging which is pretty cool. I don't think I mentioned that earlier, but it doesn't seem to be an issue anymore which is nice.

  3. #13
    Lifetime Member
    Join Date
    Aug 2013


    It sounds like you've got most of your issues under control now. Your voltage looks good. You might want to spend a bit of time working on your main spark and idle spark tables. There's probably some gains to be had there... just be mindful to keep spark variations small in your transitions between idle and non-idle conditions.

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