An excerpt taken from another Dodge specific forum, I cannot give a link due to forum rules, however it's a forum known as the internet "hangout" of the tech and performance shop guru's.

"Although you'll see some gains with the power wire mod, what you will need to do is start the PCM learning curve over. The learning will last just a couple of miles, compared to a couple hundred as the PCM is programmed to assimilate data over time. Alot of folks reset their PCM frequently just to get the gains and feeling associated immediately with a particular mod."

This was posted by a tech at a performance shop...

 

Yes, but at what ratio? Are you trying to say that the PCM will give the exact same amount of air/fuel at the exact same ratio when pushing hard on the accelerator regardless of any other factors?
Because if you are, I have seen A/F readings that shows a different A/F ratio after the installation of my LT Headers from before and then after a PCM reset by my local performance shop. This was done to test for a possible lean state after adding the headers with my current "tune".
I have first hand witnessed the A/F ratio change after the only modification being a hard reset of the PCM. I have the explanation from the performance shop on why the PCM reset showed a change, but now if, according to you, they are incorrect, myself and the hundreds of people who patronize this shop to do high end mods annually may have to change where we go. So now you've peaked my interest, how would YOU explain this change in A/F ratio at WOT after just a PCM reset?

 

Because it forces a fuel trim relearn which is what you want since the fuel trims are based on averages. Yes it'll "learn" even if it's not reset but it'll take a lot longer due to the STFT's having to slowly change the average of the LTFT's. So to cut it short....you're saving time and gas by getting a proper closed loop a/f ratio sooner.


For anyone else reading this...when you clean the throttle body do your engine a favor and remove the throttle body first. Doing it the lazy way can get solvent and carbon in the intake...not a good thing. You can also clean in a lot better and from both sides..

 

I don't see how you'd damage one either...unless you were sitting in the engine bay and stepped on a pre-cat o2.

Yea the batt disconnect will work...either let it sit for awhile after the disconnect or put the ignition to run (not start) for a few seconds to discharge any stored energy in the capacitors.

 

Thank you, thank you, thank you, Seve!!! Finally someone who knows wtf they are talking about in this thread. I love these guys who post such definitive answers that are exactly the opposite of what I've been told by performance techs, who specialize in Dodge Trucks, as well as calibration techs who write PCM tunes, have told me on numerous occasions...

 

SevereDistortion - your explanation is dead on if I compare it to my BossEFI install. The ECU has a "default" fuel cell map. It will self populate the empty cells as the car is driven in different modes. The ECU takes input from engine temp, fuel flow, air flow, air temp, engine RPM and O2 sensors to find an optimal engine output. In the case of my 347 SBF, I could feel the difference each time I drove the car for maybe 100 miles or so. Even if the Dodge ECU is not so sophisticated, I would expect it to improve as I drive.
I reset the ECU today and went for a 40 mile drive....fuel consumption is definitely improved from the stock setup based on the computer - maybe 2-3 mpg at 60 in cruise. I will drive the truck to work and back for a week and measure the difference.
Thanks guys
Steve

 

a lot of bad info
and myth in these later posts

learn what
AFF and AAF in the Chrysler PCM do
and how they relate to other automaker names
like short term and long term fuel trim values

learn how quickly these change with conditions

learn that you don't have to kill power to the PCM