what does the ecu learn after you reset it?

[pillzor]

as title says, i understand the ecu relearns certain things after you reset it and i was just curious too see what they all are.
is it just fuel / air mixtures ?

[speed_freak]

it can also learn shift times slightly. driving the car really hard after resetting tunes the shift to change a lil later in the rev range and vice versa

[Vee-ard]

it can also learn shift times slightly. driving the car really hard after resetting tunes the shift to change a lil later in the rev range and vice versa

No, it doesnt... What people always fail to understand is that the ECU is constantly updating itself. If this were true, It would do this without needing to be reset first. What you're talking about is probably all placebo effect.

The only way the shift points would really change, is if you had a tune like I do, a greenfoam one, where he sets the shift points in the memcal to be firmer, more aggressive and hold gear longer.

[Cursed CX8]

iv been told there are small gains to be had, last time i re-set the ecu i ****ed my shift points and the shifts went back to being weak and sluggish like before i had it tuned.

After a week they went back to normal.
Thats pretty much my only input

[VSPantha]

I've always been told that after you do the reset, start the car and hold it at 3000rpm for the first 8 seconds so it can do the air/fuel mixture calculation. Not sure about the shift points... I thought that they were coded into the memcal and couldn't be altered by resetting?
This might be a question for Greenfoam to answer

[hako]

You don't need to reset the ECU or have a tune to alter shift points - just press the power button and that delays the shifts same as a tune.

[-Guy-]

You don't need to reset the ECU or have a tune to alter shift points - just press the power button and that delays the shifts same as a tune.

The power button doesnt have the same effect as a tune. If so, why would people be wasting money on getting their car tuned? When you get a tune it makes the car have a bit more grunt and also delays the shifts..The power button only delays the shifts and gives a little bit more power. Does not do the same thing as a tune though.

[pillzor]

well case in point, after putting delcos memcal in my vs goes harder in economy than it did in power when it was stock.

[aceventura]

The power button doesnt have the same effect as a tune. If so, why would people be wasting money on getting their car tuned? When you get a tune it makes the car have a bit more grunt and also delays the shifts..The power button only delays the shifts and gives a little bit more power. Does not do the same thing as a tune though.

If you read Hako's post correctly he is saying that if all you want to do is change the shift points then press the power button, not change your tune. A tuned memcal changes many other parameters as well as the shift points.

In any case, I agree with Vee-ard - I would doubt that shift points are learnt.

I've always been told that after you do the reset, start the car and hold it at 3000rpm for the first 8 seconds so it can do the air/fuel mixture calculation.

This may be correct, but I have watched the engine parameters on startup, and it takes ~1 min for the car to enter closed loop mode, and it would need to do this to change any air/fuel mixtures in a sensible way.

Again, like Vee-ard said, the ecu is constantly adapting, albeit slowly (as I think it averages old and new information in some way), so it will learn this as you drive. My feeling is that you should only need to reset if you change something in the engine that will change performance.

[delcowizzid]

it will learn fuel ratio's to get it perfect at cruise will learn IAC steps to keep good idle and will change shift pressures untill it changes gears at its preset shift times in the tune if its slipping into gears the ecu will change pressure untill it changes gears withen a set time and vice versa if its changing to fast but it can only adjust so far

[VS 5.0]

Again, like Vee-ard said, the ecu is constantly adapting, albeit slowly (as I think it averages old and new information in some way), so it will learn this as you drive. My feeling is that you should only need to reset if you change something in the engine that will change performance.

So having installed a MACE CAI, should I reset the ecu then ? If so, is it as simple as disconnecting the battery or is there something else ?

[Vee-ard]

yeah leave the battery cables off for 2 minutes.

[GOTMYN]

yeah leave the battery cables off for 2 minutes.

And enjoy resetting all your radio stations, Clock etc...........
Pain in the A@@....
Oh and if your radio is security coded, make sure you have the code handy :-)

[Vee-ard]

And enjoy resetting all your radio stations, Clock etc...........
Pain in the A@@....
Oh and if your radio is security coded, make sure you have the code handy :-)

Never had to give my radio a code, and I've pulled them off heaps of times. Not many VR's have clocks either.

But if resetting your radio stations is that much of a hassle, maybe you shouldnt work on cars, seeing as how much of a pain in the ass almost any maitenance is.

[GOTMYN]

Never had to give my radio a code, and I've pulled them off heaps of times.

But if resetting your radio stations is that much of a hassle, maybe you shouldnt work on cars, seeing as how much of a pain in the ass almost any maitenance is.

It was just a reminder mate..........
Trying to give some usefull info...That's all :-)))

I'm actually disconnecting my Batt tonight, and the last time I did, I had to call Holden for the radio Code!!

seeing as how much of a pain in the ass almost any maitenance is.
Was that a statement I made?????????

[Vee-ard]

It was just a reminder mate..........
Trying to give some usefull info...That's all :-)))

I'm actually disconnecting my Batt tonight, and the last time I did, I had to call Holden for the radio Code!!

seeing as how much of a pain in the ass almost any maitenance is.
Was that a statement I made?????????

no mate, its one I made, but im not starting an argument with you because there's no point. There was just no need for your earlier comment making it sound like im giving bad advice, because that's the only way to reset it.

[GOTMYN]

no mate, its one I made, but im not starting an argument with you because there's no point. There was just no need for your earlier comment making it sound like im giving bad advice, because that's the only way to reset it.

Sorry you feel that way mate,
Maybe i worded it badly........
Anyway, keep up the good work mate, any advice is appreciated by all.

[hako]

Never had to give my radio a code, and I've pulled them off heaps of times. Not many VR's have clocks either.

But if resetting your radio stations is that much of a hassle, maybe you shouldnt work on cars, seeing as how much of a pain in the ass almost any maitenance is.

Actually, the stock VR/VS radio does have a clock as standard - it's part of the radio which must have the security code to reactivate if you disconnect the battery. Otherwise you go to GMH and pay $$$$ to get the code for your VIN.
No security code - no radio/clock.
However, I'd have to admit that most VR/VS cars do not still have the original radio.

[GOTMYN]

Actually, the stock VR/VS radio does have a clock as standard - it's part of the radio which must have the security code to reactivate if you disconnect the battery. Otherwise you go to GMH and pay $$$$ to get the code for your VIN.
No security code - no radio/clock.
However, I'd have to admit that most VR/VS cars do not still have the original radio.

My Point exactly......
I didn't have to pay, I rang Holden quoting the name of a local Auto Electrical workshop, they gave it to me over the phone :-) I was Lucky!!

[itchy123]

what if u just pull the ecu fuse for 2 minutes instead of disconnecting battery ??? lol

[Michelson4301]

After battery is disconnected Fuel economy will change on the Mass air flow based vehicles until the barometric pressure/pseudo map term is learnt. With MAP based vehicles this is instantaneous when ignition is turned "on".

[Not_An_Abba_Fan]

This is funny.....

A reset of the ECU just resets it back to factory default settings, nothing more. On pre VT vehicles you can reset the IAC by revving to 2000 rpm for 10 seconds, but post VT they self learn anyway. The ECU doesn't "learn" it uses it's pretuned maps and fuel trims to compensate for certain driving styles. If you drive like a hoon, the ECU will tend to hold gears longer in an auto, if you drive like a granny it will change quicker. The only way to alter the ECU tune permanently is to get a remapped memcal.

[moff_man]

a reset ecm sets things back to base settings, ie new plugs new oil new air cleaner, than it adjusts its self as the parts wear. newer ecm's in the vz and ve's have what is called a fuzzy logic which learns in real time. vr vs ecm have not thay are rom (read only memory) newer ones have ram (random access memory ) and is able to be written and rewritten for sofwere upgrades etc

[Andrew426]

The power button only delays the shifts and gives a little bit more power. Does not do the same thing as a tune though.

Not quite. PWR button only moves shift points about and increases shift pressures. It doesnt make the engine any more powerful.

[Michelson4301]

This is funny.....

A reset of the ECU just resets it back to factory default settings, nothing more. On pre VT vehicles you can reset the IAC by revving to 2000 rpm for 10 seconds, but post VT they self learn anyway. The ECU doesn't "learn" it uses it's pretuned maps and fuel trims to compensate for certain driving styles. If you drive like a hoon, the ECU will tend to hold gears longer in an auto, if you drive like a granny it will change quicker. The only way to alter the ECU tune permanently is to get a remapped memcal.

Yes I am aware and understand what you are saying. I am merely pointing out that the Base setting for the pseudo map term that the VS/VT/VX/VT V6 pcm's use for calculations is usually too low and requires a little driving time to learn up to were it should be. This is the altitude correction factor that DOES effect base fuelling although the oxygen sensors do trim this back to stoich at cruise and this trimming DOES change your full throttle AFR's So long as LTFT cell 16 (or actually labelled15 which ever way you look at it) has had correction applied to it.

All of the ECM/PCM's used by holden learn to some extent to accomodate for wear and general conditions, usually all this is lost when you disconnect the battery. All the LTFT's, PAM's, KAM's, IAC ACC steps are set back to base settings. This is why a car may shift the auto hard or slip on changes, why the engine may hunt for idle, go high or stall and why fuel economy can be brilliant or piss poor BUT only until every system has had sufficent time to carry out what has been labelled in OBD2 vehicle systems a drive cycle.

OBD2 Fault codes are a whole different kettle of fish.