I've been looking around and can't find an answer so I figure I'll ask here. How does the tune actually work in the ford PCM? We have multiple driving modes that change how the vehicle functions. Does the PCM have a dedicated program for each mode or is there only a single base tune and each mode makes a fixed set of changes to it? For example, if I want a totally stock program in normal mode and only have tuned changes apply to the sport driving mode, is that possible?

 

Good question. However, you're thinking about it a little backwards.

The drive modes affect shift points, pedal response (torque demand as a function of pedal input), active exhaust positions if equipped, and various other minor things in the background. When tuned, changes often apply to a/f ratio, spark timing, flex fuel, rpm limits, fan temps, etc. So if the tuning changes are outside of shift points and pedal response, then changing drive modes would not have any affect on the tuning changes.

 

The sport mode for example has no change in ignition timing or cam position? It's all shift points and throttle response?

 

correct

 

Never would have guessed that. I always assumed it changed the timing curve to favor max HP instead of economy.

 

Nope, drive mode doesn't change WOT timing. Spark timing is calculated based on borderline knock, max efficiency, max cylinder pressure, and torque control, then the lowest value selected. It turns out that max power timing is the same as max efficiency timing.

 

This is some valuable information!
Thanks for the clarification.

 

As from Google, and fords website.

Normal mode is for balanced, everyday driving, while Sport mode is for more spirited driving by increasing throttle response and holding gears longer for quicker acceleration and enhanced performance. Normal mode defaults to the most efficient settings for daily commuting, whereas Sport mode prioritizes a more engaging and responsive driving experience.

 

Thanks, but that really doesn't help the Tuning question. I understand how the modes change the driving feeling, but was unsure exactly how on a tune/software level it made those changes.

 

As it says, throttle response and holding gears longer.

So in theory, the tune does get changed to advance timing to get more of a response.