Results 1 to 3 of 3

Thread: Idle tuning/stalling help

  1. #1
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    13

    Idle tuning/stalling help

    This is a 5.3/4L60E swapped into an older truck. Its got a summit truck cam (210/219), Stock 78?MM cable throttle body. 3000 stall converter. 0411 ECU.
    I have the VE table tuned in over a wide area and it runs great in traffic, on highway etc. Also have the idle RAF tuned correctly (I think) using the Russ K methods found on this forum. The problem arises mostly I am stopped and changing from D to reverse etc and backing up with light throttle on/off etc. Rpm will drop to nearly 400 RPM at some spots.

    Its a 2 Bar OS upgrade. Base tune was a 2002 5.3 truck, cable throttle. I have tweaked the throttle stop so IAC is 50-60 at hot idle. Problem really only is bad in reverse, I wonder if this is due to the added load from the line pressure increase in the trans in R.
    I had played with the idle under/overspeed spark tables but they don't seem to be doing much. I have them so at 200 RPM under it should be adding 12 degrees, But in the log it seems like its only adding 1 or 2.
    I took this short log of the issue.
    19-09-21 13-09-54.hpl
    Last edited by grumpy1; 3 Weeks Ago at 05:08 PM.

  2. #2
    Tuner in Training
    Join Date
    Sep 2013
    Posts
    20
    Looks like your low rpm AFR isnt happy which can make things worse. I would make sure that is good first.
    Also I turn off LTITs on any cam car.
    you might want to add some air to throttle follower? and or redcude the IDLE Proportional in the idle PIDs

  3. #3
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    13
    Yeah the AFR. So this is a centri supercharged setup and I have relocated the IAT sensor to the intake behind throttle body, and have the charger intake sucking from right behind the grille. But still the IAT's go way high if not moving. The charger itself gets heat soaked and warms the air passing thru quite a bit (even out of boost) I have spent hours tuning the VE table and its within 2% everywhere, As long as I am moving or just stopping for a moment. This is open loop STFT and LTFT disabled.

    When I get into a situation (Like I have shown in this log) of low/no movement and extended idling and maneuvering , The AFR error will show lean as much as 5-8% I have seen. Its as if the speed/density calculation is over leaning the fueling based on temp.
    If I use the scanner control tool (Which i'm not sure what numbers its based on ? VE ?) to override the AFR leaner the stalling/droop problem is much less, like 100 RPM better. So it seems like it wants to be lean down there. How does one tune the 400 rpm column.....
    I tried making the 9x9 area of cells surrounding the idle point all the same number but that didn't help and the afr error was bad in those cells.