Over at TDS i saw some talk about disconnecting the batterys for a system power cycle and then people seeing better fuel economy after the reset?!?!
This was more pronounced after towing heavy then no towing...something about the pcm/tranny relearning things and tweeking up the efficiency.
Don't know...but it caught my attention...hmmmm...interesting. Anyone have info on this phenomenon?
Nut

 

Posted about it many, many times myself. I do it every few months to teach it to be more aggressive for when the chip starts feeling soft.

 

How long do you have to leave it disconnected?

 

Orezona
I've heard of the same thing PSnut is talking about, I disconnect
the batteries when i change my oil, It takes myself about a hour because i take my time, A Ford Tech told me a hour was plenty time to reset the computer.
I'm not 100 % sure on 1 hour, I just took his word, I'll double check and let you now. I'm going to the stealership tomorrow.

 

I'd like to see some posts on peoples experiences doing this reset procedure because i will if it means any efficiency gains.

 

I believe that when you have the batteries disconnected long enough, you can tell that the PCM resets as soon as you turn the key to the on position. Both the speedo and tach will go full scale and then return to zero as part of the initialization sequence.

 

I had my batts diconnected today for about 20 minutes to install my new GPR, and when I turned the key, the speedo and tach pegged, and then fell back to zero.

 

Stopped by the dealership to check on some parts, I ask the tech about resetting and he said 15 minutes was long enought.

 

I'm not sure what the battery disconnect time should be, but maybe Mr Ford's self learning functions are not as good as what he thinks the defaults should be. Maybe I'm off base, but somewhere I recall reading that these computers learn the users driving style from about the last 30 or so cycles and they try to maximize the vehicle proformance on that history. Maybe our own driving history is not as good as Henry's default settings. I hadn't thought about it, but what if I drive city for 3 months then I change to a highway trip. Until I retrain the computer it still thinks I'm in the city and responds based on that.

What I'm thinking is that he knows his engines better than how I drive regulary. Most of the time I drive in the city, but I find that I tend to change the oil right or shortly before I go on a trip. So if the computer (EMC/BCM/GEM...) keeps my last 30 or so start cycles for around town and applies them to the highway I'm not going to be maximized for the highway. The same would be true if I went from highway to city driving.

As I recall reading somewhere the computer will try to tune me in as best it came based on my driving history. So if I'm going from mostly City driving to a Highway trip or the other way around - mostly Highway to City trips = I'd say let Henry Ford make a best guess for me and plug his numbers and work best.

So if you change your driving habits often - reset them and let the computer decide for you (or make a best guess).

 

What's The Easiest Way To Disconnect.....
Take Both Positive Leads Off Or Take Both Negative Leads Off ?

May Want To Try This Myself...... This Also Means Resetting All Of The Radio Stations.

 

I just took off both positive leads. And I didn't have to reset my radio stations. But the Speedo and Tach pegged out upon the first start after re-connect. So.....I don't know, I'm just an FTE junkie.

 

Two minutes will do the trick if you walk around and flip the headlights on with the batts unhooked.