Auto Tune is a feature in the Dynojet Power Vision that helps riders refine their fuel maps. By using O2 sensor feedback, Auto Tune generates tune corrections for improved performance. Riders often ask, what is Auto Tune and how does it work? Let’s break it down.
Closed Loop vs. Open Loop
The Harley-Davidson Delphi ECM uses a speed density system. It predicts airflow based on sensors like MAP, IAT, engine temperature, and RPM.
Closed loop: Uses O2 sensors to correct the air-fuel mixture in real time. Fuel trims help maintain proper AFR.
Open loop: Relies only on ECM programming without O2 sensor feedback. Adjustments come strictly from the calibration file.
Understanding this difference is key to knowing how Auto Tune applies corrections.
Auto Tune Basic
Auto Tune Basic works with 2007–2020 Harley models. It’s free and uses the factory narrowband O2 sensors. The system forces closed loop across the operating range, generating corrections for light to moderate loads. Keep in mind that narrowband sensors only read 14.3–15.2 AFR, so data collection has limits.
Auto Tune Pro
Auto Tune Pro works with 2001–2020 Harley models but requires the Auto Tune Pro kit. This kit includes wideband sensors and a controller that connects directly to the Power Vision. Wideband sensors read a broad 10:1–18:1 AFR range.
Unlike Auto Tune Basic, Pro mode is open loop. It logs wideband AFR data across RPM and throttle ranges, including wide-open throttle. Riders then export corrections back into the base tune. Many aftermarket exhausts already have 18mm O2 bungs; if not, the exhaust needs modification.
Target Tune
Target Tune takes things further. For 2007–2020 Harleys, it uses wideband sensors for real-time closed loop fuel control. The system requires flashing the ECM with a Target Tune calibration, enabling wideband compatibility.
Target Tune constantly adjusts AFR to stay on target, using the bike’s closed loop strategy. AFR targets can be customized in WinPV, while Target Tune Auto Tune mode creates corrections similar to Basic and Pro.
Tips for Running Auto Tune
Run three 20-minute riding sessions for best results. Export corrections after each session.
Always re-flash the final corrected map when finished.
Expect some rough running during warm-up while in Auto Tune mode.
Set Min/Max engine temp and RPM for Sportster or V-Rod models.
Adjust Min MAP to avoid overcorrection at light load or decel.
For example, if idle MAP reads 38 kPa, set Min MAP to about 33 kPa. This stabilizes corrections and prevents erratic fueling changes.
Final Thoughts
It’s a powerful tuning tool inside Dynojet Power Vision that adapts your Harley’s fueling with precision. Whether you choose Auto Tune Basic, Pro, or Target Tune, each option provides riders with greater control and smoother performance.
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If you need to visit Dynojet’s website directly, visit: www.dynojet.com