ECU will learn?? Huh??

[SaNdSuKkA]

*EDIT* I read the US Patent on Method for Controlling Ignition Timing of an Internal Combustion Engine 5,000,149 referenced from a thread on Nasioc. This is probably a system similar to what Subaru uses.

According to what I've read, it shouldn't really take more than a few hours for the ignition timing to settle in if even that long. And also it would seem that the system is constantly testing and adjusting the timing advancement based on engnie knock. Now I guess the question is, what else does the ECU learn besides ignition timing advancement? Because if it does nothing more, then I think doing an ECU reset would accomplish very little.

-------------------------------------------------------------------------------------

From the Sticky thread about Cobb AP and ECUTek, "The ECU will learn and adapt to your driving style." http://www.legacygt.com/forums/showthread.php?t=8084

 

How the hell does that work? I've also read that the ECU takes a few days sometimes to ajust to new AP maps. But how does this work? Also if you drive really conservatively for awhile and then change your driving style, will the ECU re-learn? This concept blows my mind. I guess I just can't understand how the computer will learn my driving style. Cany anyone dumb this down a little for me ? Are you stuck with what your ECU learns? Can you teach an old ECU new tricks?

 

Thanks

[Scotty]

You can reset the ECU by disconnecting the power and holding the brake so the brake light comes on till all the power discharges. Vishnu posted a way to speed up the learning process to gain some more power temporarily, it's posted on naisoc.

 

I don't know the exact mechanisms involved, but often there is a baseline setting and the setting is changed depending on how you drive. For instance, on the automatic transmissions, if you start the car and started doing a lot of full throttle or really fast throttle inputs, it will change the shift program slightly so that it'll hold a gear to higher RPM and also down shift early.

[AWD_Rules3830]

IT WILL LEARN >>> and will assimilate us into its MATRIX >>>

[elpete77]

Super Trapper Keeper, you're so cool. I love you Super Trapper Keeper.

[KartRacerBoy]

Beam me up, Scotty!!!

[elpete77]

Beam me up, Scotty!!!

[TrashTrampoline]

Old technology, my 98 Jeep Grand Cherokee was a learner.

[rallispec]

nothing to fancy i'm sure... probably just averages out your torque demand (throttle position) and then comes up with a fuel mixture / timing ratio to best suit that.

 

if your easy on the throttle more than not - it adjust differenty than if you are constantly pushing it to the floor.

[LIZARD]

Y'alls all dint dummit deowwnnn fer he-imm.

[-TT-]

http://www.sportcompactcarweb.com/projectcars/0309scc_projwrx/

 

start about 4 paragraphs down.

[SaNdSuKkA]

hmmm ok, so then the ECU is constantly adapting, not just locking in the first few days of driving style? Correct?

 

And if this is correct:

 

Lets say you had to identical Legacy GT's exept one driven conservatively and the other aggressively. Then you took them to the track and had the same driver put on a few runs on each. Since the ECU can take a few days to adjust, the aggressively driven car would be faster hands down?? This kinda irks me. I want my car to be as fast as it can be at ALL times

[BDII]

He has a learning CPU.

[SaNdSuKkA]

guys, i'm sorry, but i'm truly interested in this topic. Could you please restrict your posts to helpful information, thanks

[-TT-]

, the aggressively driven car would be faster hands down?? This kinda irks me. I want my car to be as fast as it can be at ALL times

 

its not that the more agressively DRIVEN one would be hands down faster unless it was more aggressively TUNED. it just means that if there is more detonation happening the ECU will pull timing to help your engine to not explode.that pulling of timing means less power. therefore the car that has crappy gas is slower and for good reason.the reason it takes time for this to be noticed is because it doesnt sample your crappy gas until it burns it. either than that at the same tune and same gas they will run the same

[SaNdSuKkA]

Thank you Turntable. And by your reply it seems certain that the ECU is constantly adapting.

 

And another thing. When you add on mods, does the ECU relearn with the new parts or do you have to reset it?

[-TT-]

it depends on the mod. if it is an ECU mod of course you will have to reset it.

if it is a mod that improves exhaust/flow (up/dp) you will feel the difference simply because how could you not? (flawed yet true logic) but some maintain that a reset does eek out a little more....but i dunno if i believe that (or care for that matter)

[-TT-]

the ecu starts with a conservative tune for knock detection and makes it a little more and a little more agressive during the first hundred miles of a reset of the ECU

-if everything is good (gas, intake temp, no knock detected) it advances fully

-if bad gas or knock provoking situations are encountered, it pulls timing(like it would with bad gas or HIGH intake temp) to save the engine

 

there is also a way to trick the ecu into giving you full tuning for ideal conditions all at once after resetting it. but that should only be done if you are sure it is not knocking and has the least possibility of knock

[red beast]

from nasioc

 

http://forums.nasioc.com/forums/showthread.php?t=302047&highlight=ecu+learning+vishnu

 

 

 

 

 

Just a little trick that has been shown to accelerate the factory ECU's ignition timing learning process.

 

Background: There is something called "Ignition Advance Multiplier". It represents, by some complicated algorithm, the average learned positive knock correction applied to the ignition maps. It's represented in 1/8th degrees increments. 1 being the lowest and 16 being the highest (1/8 to 2 degrees in absolute terms).

 

The "happier" (knock free) the car is, the higher the number will be. Conversely, the lower it is, the more knock prone it is. This number, after ECU reset ore ECU swap defaults to 8 and usually creeps up to 16 (if well mapped) through normal driving. Depending on driving characteristics, this can happen within a few hours or a few weeks. Well, here's a way to make it happen in about 5 seconds ....

 

First: With the car fully warmed up, reset the ECU. This can be done by killing power the ECU or by simply pulling off the neg. battery terminal and pressing the brake pedal for a couple of seconds.

 

Second: Drive to a nice open road without traffic. Don't go on boost until you get there. Put the car into gear (3rd gear works the best) bring the revs up to 2600rpm. Push the go pedal down slightly so boost stays right around 2-4psi. You will need to MAINTAIN 2500rpm and 2-5psi for approx 5 seconds. You can do this by left-foot braking gently as to prevent acceleration. During these few seconds, the advance multiplier (which you can't see so you'll have to trust me) will go from 8, to 12 and then to 16. Works like a charm. And on our reflashed ECU, is worth an immediate 10-20 horsepower

 

In an attempt to save a lot of dyno time between reflashes (when the advance multiplier resets itself), I do this little trick after every reflash. In a typical dyno session, it's not unusual to reflash the same car up to 5 times. On the dyno, all I need to do is tell the dyno to hold revs to 2600rpm. Then I just lay on the throttle until I see a few psi of boost... Bingo!

 

Warning: This little trick artificially speeds up the learning process. This is only a good thing if the re-mapped ECU is mapped properly. If there are trouble-spots where knock is present, this trick will make it even more present. So be careful!

 

Cheers,

shiv

http://www.vishnutuning.com

[SaNdSuKkA]

I read the US Patent on Method for Controlling Ignition Timing of an Internal Combustion Engine 5,000,149 referenced from a thread on Nasioc. This is probably a system similar to what Subaru uses.

According to what I've read, it shouldn't really take more than a few hours for the ignition timing to settle in if even that long. And also it would seem that the system is constantly testing and adjusting the timing advancement based on engnie knock. Now I guess the question is, what else does the ECU learn besides ignition timing advancement? Because if it does nothing more, then I think doing an ECU reset would accomplish very little.

 

Oh and thanks Turntable and Red Beast :-P