2011 Explorer Fuel-Cut - DFSO

[GaryG]

I've confirmed aggressive DFSO (deceleration fuel shut off) in the 3.5L V6 with my Scangauge II. For those of you who don't know what DFSO is or how it works, I'll explain. In order to save fuel, the automakers are designing engines and transmissions to keep the engine at an idle RPM while decelerating and using no or little fuel. Ford uses the term DFSO but the term DFCO is used by other automakers where the C stands for CUT instead of S which stand for SHUT in a Ford.

 

This is all possible by the computer (PCM) to cut fuel to the cylinders and use the transmission to hold the idle with the drive wheels. This is like engine braking but more controlled to hold the RPM's at an idle speed. When the RPM's are held at an idle by the transmission, the engine can smoothly restart under fuel power when you accelerate again.

 

Now, understanding how Ford has designed DFSO and using it to save even more fuel while driving is how hypermilers get better than the EPA ratings. Your average driver gets fuel-cut and doesn't even know it but if you know how it works, you can use it to the maximum and get better MPG. The 2011 V6 Explorer is designed to get what Ford says and I confirmed, "aggressive fuel-cut". This means at any speed above ~25mph, after about 3 seconds with your foot off the gas pedal, you are burning no fuel and increasing your mileage like a hybrid in electric drive. You can see Fuel-Cut with a Scangauge II when the Instant MPG reads 9,999mpg and confirm it with what is known as OPEN LOOP.

 

The owner of cleanmpg.com ask me to post some pictures of my new 2011 Explorer in the Photo Gallery there and I added a photo of my Scangauge in it while in Fuel-cut. Take a look: http://www.cleanmpg.com/photos/showgallery.php/cat/500/ppuser/36