10 replies to this topic

[jeffnat68]

If your car is running a little rough and not as it should be, would it be a good idea to reset the ecu?Its just a thought because when my sky box has a moment and goes potty all sky engineers say is to unplug the box from the mains for a while to reset it.Also when my smart fone freezes all I do is a reset and its fine again.So I am thinking that if your car is running a little rough, then by reseting the ecu it should go back to factory defaults,Obviously unless there is something mechanicaly wrong with car that is.Any thoughts on this????

[FOCA]

The ECU differs from the sky box/ most consumer domestic electronics because it has a "learning" ECU, after a reset the ECU "relearns"

Resettiing the ECU can often help poor running problems (to an extent) - watch you don't loose your radio code

[jeffnat68]

No worries foca,I have the code written down.

[jeebowhite]

As FOCA said, just disconnect your battery for half an hour to an hour, and it enters learning mode again. drive it as you intend to drive it all the time, to get the best out of it. The car pretty much constantly adapts to your behaviour, but think of it like MPG, if you floor it for the first two hundred miles, your average MPG will be low, if you then start to drive like a granny, it slowly picks up MPG.

If you start off driving like a granny, you start off with a high MPG, and if you put your foot down afterwards, it goes down slowly, and recovers more quickly.

[jeffnat68]

Well I reset the ecu today and took it for a spin.Gonna take it out for a long drive tomorrow and see if there is any difference in running.Will keep you informed...

[cuke]

Hi, car ecu's don't adapt to the driving behaviour, its a myth as they are all the same, so all you need to do is drive it under various conditions so the sensors can be recalibrated. Of course if you always believe this I picked up from a quick search in goggle about ecu learning myths: "Oh! It learns via the Air Bag interface. After it deploys the air bag interface, you're gently knocked into a altered state. It reads your mind, finds out what you know, how you drive, and how many days you wear matching socks in a week. Then it tunes the engine accordingly." Scary stuff...

[FOCA]

Hi, car ecu's don't adapt to the driving behaviour, its a myth as they are all the same, so all you need to do is drive it under various conditions so the sensors can be recalibrated. Of course if you always believe this I picked up from a quick search in goggle about ecu learning myths: "Oh! It learns via the Air Bag interface. After it deploys the air bag interface, you're gently knocked into a altered state. It reads your mind, finds out what you know, how you drive, and how many days you wear matching socks in a week. Then it tunes the engine accordingly." Scary stuff...

The ECU >CAN< adapt to your driving style, -

The throttle is merely a potentiometer (variable resistor ) that "tells" the ECU how much throttle you require, it is not connected directly to the injectors etc, the ECU "decides" the amount/ duratoin of fuel injected

The ECU monitors all kinds of data, if it detects a problem, for example "knock" it may "back off" the amount of fuel injected, irrispective of the amount of throttle,

It may decide to put the car into "limp home" mode, this is to protect the engine and to keep you going to get you home

The ecu knows how much throttle you use, how many revs, when you change gear, your speed etc

It can adapt to a clogged air filter, a clogged CAT or DPF (if fitted) even engine wear (this is to maintain acceptable emmision levels over the cars' long service intervals and/or lifetime) or even some faults (to a certain degree)

It can adapt to poor quality fuel or extremes (hot or cold) of temprature

So the ECU (engine control unit) can do a lot more than just adapt to your driving style
But it does not know what ypu had for breakfast/ or the color of your socks!

A modern car has a "learning" ECU, a 30 year old (petrol) car has points, and a distributor, and cannot "learn" - lets not get them mixed up




A story of 3 "identical" cars -

The cars may leave the factory the same,(in theory) but then they are not driven/ seviced the same - 3 "identical" cars -one gets sold to a rep that gives it a mercyless thrashing up and down motorways, a taxi driver gets another a little old lady gets another (drives it once a week, never over 30mph , uses 2 gears - 1st and top) 5 years later, the taxi driver has gone through 3 DMFs/ clutches and done a high milage - but the car was serviced regularly, the little old ladys car is a low milage, but all she did was put fuel in it and it was neglected (the last service was the last one under warranty- ouch) - the reps car was written off, cut and shut then "clocked" - may seem extreeme/ stereotypical- but these are 3 "identical" cars

[cuke]

Hi, that is exactly what the ecu does perform, it learns what the engine is doing and then makes changes accordingly to the sensors to prevent damage and makes sure that the co2 and mpg is optimised.It does that constantly at many times a second but what it will never do is 'learn' what the the driver is doing, thus it cannot know that Fred is in the car not Freda. Once the engine it off there is only the calibration of the sensors that remain in the memory of the ecu, plus the programming put in there by the manufacturer.. ECU's aren't, and can never be, that sophisticated. Limp home mode will only be instigated when a fault code come through. What you describe is nothing to do with the ecu but how the various parts of the engine have been stressed, or not as the case maybe. A dmf is a mechanical component and not even physically wired to the ecu either, so how the ecu would react to that I don't know. Not really a good example to use as we aren't talking about mechanical changes due to the way it is being driven.

[FOCA]

Perhaps we should substitute "learns" with "adapts"

The phisical and electronic parts do interact together

The DMF was just a simple, easy to understand reference to how "identical" cars are driven / serviced differently, - ie the (theoretical) taxi driver wearing out 3 DMFs - so the "identical" cars are not identical

The car cannot tell if Fred or Freda is driving, but can tell, how hard/ how much throttle/ how many revs/ speed/ gearchanges Fred/ Freda is using, if Fred/ Freda runs low on fuel and the "low fuel" light comes on, the ECU will adopt a "fuel saving" strategy
to stretch the MPG to the next refill

If Fred drives hard, "redlines" the engine through the gears, full throttle when overtaking etc, the ECU will learn


adapt to this, by adjusting the engines parameters to suit, at least to give the correct air/ fuel mixture and protect the motor from detonation with Freds hard driving, i would like to think the ECU tries to get the best performance out of the engine by fine- tuning the parameters, at the expence of economy

Freda, on the other hand, does the shool run, and drives mostly at 30mph, short-shifts, and hardly uses any throttle, the ECU "reads" this, and learns adapts to this too, to give the correct fuel/ air ratio, and potentially the best fuel economy

It is a matter of perception how basic or sophisticated any system is, compared to plugs/ points and a distributer, a modern car is VERY sophisticated, we take computers, smart phones etc for granted, something that looks simple on the outside, may be extremely sophisticated "under the hood"

In the 90s/00s, there was an advert that claimed the BMW 5-series had more computing power than NASA had to put a man on the moon.

Comparing cars to tvs -

When i leave the room, my (big Sony LCD ) TV switches itself off to save power, then almost instantly switches itself on when i come in again, the first few times, this was a surprise, and i thought it was "cool" - now i dont even notice, it has Freeview HD, and i connected a 2-terabyte hard-drive directly to it to record (without any external devices). A few years ago this would have been unheard of, but the TV is already obsolete (no 3D) so the tv is either a stunning high tech massive flat screen premium brand High-Definition device, or an (6-month) old piece of junk with no 3D, depending on my/your perspective

It seems simple to me, but my mum has a similar TV and i often have to show her how to record, watch a DVD etc, in actual fact, its complicated/ sophisticated, -

So are the gubbins of modern cars, thats why they often leave mechanics/ main dealers/ technicians/ fuel injection specialists/ auto elecricians and even people on forums "scratching their heads"

[jeffnat68]

Very interesting foca...I just got a 3d tv but its already out of date lol..it has not got ultra high definition just hd...Any way back on topic,After reseting the ecu a few miles have past and have not really noticed any significant difference in the car apart from once for about 5 mins I was getting 99.9 mpg according to the digi readout,but it soon balanced out again.

[cuke]

Hi, anyone who believes that a ecu actually learn the driving behaviour of the driver is only fooling themselves.A ecu is not a cpu and is only a small microprocessor with a limited amout of memory and is far far less complicated than a processor that is fitted inside a modern PC. It simply hasn't the capacity to learn anything and can ony process the inputs from various sensors. I think it needs to be understood how a ecu works before making assumptions about what it can do, and there are no myths about it

There is also no scientific evidence out there to support the myth that ecu's learn driving behaviour whatsoever. If you to get into two cars, say three years old, even with different mileages on the clock, one having been thrashed, the other having been driven gently around town, no-one would be able to spot any diffences in the driving characterisics caused by the ecu altering anything, unless there is a fault of course, if this was true then there would be a hell of alot unsold cars on dealerships forecourts. If it was the case a ecu learned behaviour making a difference in the engine why is the business of clocking a speedo so popular, because it is very difficult, if not impossibe to tell the differences. Even if a fault code is cleared by resetting the ecu, which is rare, that is not caused by the the ecu learing the driving patterns of the driver, all it doing is clearing its memory.

TV's, and their internal processors by the way, do not compare as they do not work in the same way as a car ecu and a TV isn't obselete because it hasn't 3d, as this is only a marketing ploy to get us to buy more TV's.