RevGTO:

Thanks for the report.

It was very informative. Believe it or not that swing in LTFTBEN's is not that uncommon. Weather changes, fuel type, even your fuel level can sometimes alter the Trims.

But, it is important to get consistency. And it sounds like you have. Your right, probably by run 3 you can be dialed in.

Trims on Decel. Always an interesting topic. So many of these Trims get locked in early on the learning curve. Just depends on your year of vehicle and what Fuel Trim Cell (FTC) you are in. Sometimes Decel gets it own unique FTC, and once its hard to budge some of the Trims in those cells.

More worrisome is PE. This method relies on the narrowbands and its relationship with LTFTBENS. Obviously PE ignores the narrowband feedback and requires a little more finesse to get it right. Suffice to say, if you can enter PE Mode with 0+ Trims, then you just need to look at the % difference between Commanded and Actual AFR (BENS) and adjust the MAF Freq accordingly.

Perhaps at some point the Tutorial can link to 'Methods of WOT Turing'..as it does require a some different approach. The challenge in writing a Tutorial was not only where to begin, but where to stop. Hopefully in the future we can figure out a way to combine Idle and WOT Tuning into a series of Tutorials.

Thanks for the feedback. Hope you can get your WOT Tuning done. Its only 10% of the VE Table, but arguably the 10% that is the most fun !