Auto Tune/Target Tune Terms & Definitions

  • What is “Auto tune”
    • Auto Tune is an application in Dynojet Power Vision that allows users to quickly & easily generate tune corrections based off O2 sensor feedback utilizing either the factory narrowband sensors or the optional wideband sensors. There are three versions of Auto Tune for Power Vision: Auto Tune Basic (uses the factory O2 sensors), Auto Tune Pro (uses the wideband Auto Tune kit), Target Tune-Auto Tune (uses the wideband Target Tune kit)
  • Closed loop vs Open loop
    • The H-D Delphi ECM is a speed density system, meaning fuel delivery is based on modeled airflow. It uses feedback from various sensors to predict air mass entering the engine; primarily the MAP sensor, IAT sensor, engine temperature & RPM. It uses VE (volumetric efficiency tables) to model the airflow in the calibration and the ECM is continually adjusting for relative conditions such as ambient temperature, alititude, etc..
    • A Closed loop system monitors & corrects the air fuel mixture using the O2 sensors to maintain the air fuel mixture commanded in the calibration. Most applications use short term & long term fuel trims.
    • An Open loop system does not use correction from O2 sensors, it relies on the ECM programming specifically.   

Auto tune basic

  • For 2007-2020 Harley models
  • Free and requires no additional equipment
  • For use on bikes that have OEM closed loop fuel control and stock narrow band sensors
  • AT Basic uses closed loop to populate tune corrections that can be exported directly back to your base tune
  • Note that this uses stock narrow band sensors and they are only capable of measuring in the 14.3 – 15.2 AFR range. AT Basic temporarily forces closed loop over the entire operating range. This is best suited for populating corrections from light to moderate loads

    Auto Tune Pro

  • For 2001-2020 Harley models
  • Requires purchase of Auto tune Pro accessory kit
  • Uses wide band sensors and a controller which connects directly to the Power Vision via CAN cable.
  • Note that wide band sensors are capable of measuring AFR from 10:1 -18:1
  • Works in conjunction with PV to read & store real time AFR (while you are riding the bike) throughout the entire RPM/throttle position ranges including WOT.
  • AT Pro is open loop, it doesn’t make real time closed loop changes. It uses data from the wideband sensors that is logged in the Power Vision to accurately populate tune corrections which are then exported directly back to your base tune. The commanded AF mixture is temporarily set to 13.0 when in AT-Pro mode.
  • Mention that a lot of aftermarket exhaust systems come with 18mm bungs but if not you will have to modify your exhaust to accept the O2 sensors

    Target Tune
  • For 2007 – 2020 Harley models
  • Requires purchase of Target tune kit. TT supercedes AT-Pro in most applications except early non-O2 sensor equipped bikes.
  • Uses wide band O2 sensors (18mm bungs in exhaust) for real-time fuel control over the entire operating range and is full configurable.
  • TT wideband sensors plug into factory O2 harness
  • Bike must be flashed with special  Power Vision “Target Tune Calibration” that enables Target Tune.
  • Transforms stock ECM to be able to read & interpret the wide band O2 sensors and adapt them to the existing closed loop adaptive fuel control strategy in the Dephi ECM
  • Once flashed TT operates in real-time closed loop, constantly adjusting for all conditions and making the changes to keep the AFR on target
  • AFR targets can be set via WinPV and all the regular tuning parameters that are exposed to you in WinPV are still available.
  • The TT-Auto Tune mode allows users to generate tune corrections and apply them back to the base tune like AT Basic & Pro. TT-AT uses the same AFR targets as your base map when in this mode.

Auto Tune Tips:

When running Auto Tune we recommend running three, 20 minute sessions of mixed riding. Between each session export your learned correction and then re-enable this tune for your next Auto Tune session; when you are finished flash the tune from Tune Manager. You can do these sessions on different days etc.. just be sure under normal riding conditions to flash your non-Auto Tune map (don’t just disable Auto Tune) When in Auto Tune mode Power Vision makes several temporary changes to the tune to allow maximum data collection and learning.

Note the bike may run a bit funky when in Auto Tune mode, especially during warmup.

It is best is many cases to get the bike to operating temperature and then enable Auto Tune.

Auto Tune Settings:

The default AT Settings are setup for Big Twin models, if you have a Sportster or V-Rod you will want to go to SETTINGS on the main Auto Tune screen and adjust the Min/Max parameters for Engine Temp and RPM. These values can be found in the Power Vision user guide. 

It is also helpful to set the Min MAP pressure in all applications, this prevents overcorrection of the tune in the light load & decel areas. The easiest way is to start the bike and go to the green Auto Tune histogram screen. You will note the MAP pressure  when idling which is displayed in the upper left corner, you will then go back to the Auto Tune Settings screen, select Min MAP and enter a value approx 5kpa lower than the MAP your bike was idling at. For example if your bike was idling at 38kpa you will enter 33 under Min MAP.  


For detailed information & instructions on running Auto Tune >click here<

For a video overview of Auto Tune >click here<