Mods Reversed by ECU

[toyxrunner]

I was looking around on another forum and found some interesting stuff about the stock ECU of most new vehicles.

From what's being said is that if you put a better intake or better injectors your computer after a few short hours will start compensating for better flows and start reverting everything back to stock specs.

the newer hondas will start adjusting the fuel maps as a result of the emissions and essentially detune the car.

A simple solution other than getting your ECU rewritten is to wire in a power on off switch to the ECU and switch it off and on from time to time resetting the "correction" that the ECU has made. This is a lowsy way to do things though.

http://www.technosquareinc.com/2004.htm (http://www.technosquareinc.com/2004.htm)

Shows that the 350Z has some major issues with this, sucks for them.

Go ahead and discuss as you like.

[toyxrunner]

ok here is a direct quote;

The ECU will not undo mods. Mods are usually hardware related and the ECU can not unbolt anything.

What the ECU will do is always maintain an airfuel ratio of 14.7:1 in closed loop mode. I see these kids all the time with an AFC up on their dash with fuel jacked in with an increasing amount. They think it will make their truck run richer in the "midrange".

In closed loop, if you jack in fuel, the ECU will just adjust it back out to maintain that proper mixture. The only time you have control over the mix is in open loop. The ECU does not use any feed back device so it has no idea how rich or lean it is. This is why you will never get a check engine lite from a super lean mix at WOT with a supercharger.

In closed loop you have to work with the ECU not against it. This is why we preach using a scan tool to set up your closed loop map with a linear controller. You get it right and get those fuel trims down close to zero the truck will run better, have better throttle responce and so on.

When I hear that people get a performance gain or loss after an ECU reset that clearly shows that they do not have their maps properly set up. There should not be any change in precieved performance with an ECU reset and there should not be any "learning" time.

Timing on these newer cars is also "dynamic" meaning it is always self adjusting and alway trying to run it as far advanced as possible until it sees knock. When it does, it will pull it back slighlty and then advance it slightly until it sees knock again. It is always trying to keep the timing at the kniock threashold. These folks that say they are getting much better performance with an engine that has been converted to forced induction by advancing timing are not understanding this basic things.

If at WOT and full boost and RPM it knocks at 19* BTC and you jack in 5 degrees advance with a piggy back it will still ping at 19* BTC. So, the ECU will pull out 5* and it will be running at 14* and you have the 5* added in so you are right back to the 19* ping threashold and have accomplished NOTHING.

[02sonoma]

ummm, it looks like it makes sense, but i dont know nothing bout no crap like that.

[brewthru85]

this rumor or whatever you'd like to call it has been around for some time now.

[toyxrunner]

this rumor or whatever you'd like to call it has been around for some time now.
That site concerning the 350Z kinda of confirms that this is true. it might now undo your mods but it esentially compensates the emisions and timing and whatever else to produce stock emissions and such resulting in a detuning of the vehicle.

The only way to fix this is to reset the MAPs and such of the ECU. or just getting a new ECU built for your setup. And if you have this ULEV crap as some of these new 350Z's have your crap out of luck until you get a whole new ECU installed or find a way to defeat the fact that you can't flash the computer to how you want it because it will delete it or not accept it to begin with.

Really sucks for those that are buying these new vehicles and then realizing that they have to completely redo the entire ECU before they can worry about making any serious performance MODs top there cars or trucks.

Yes I type novels, but they seem to have good info.

[k20hatch]

Im running the hondata ecu reflash...with 440 injectors..