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post #1 of 40 (permalink) Old 09-09-2004, 08:33 AM Thread Starter
 
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The engine computer

Talked to the sales guy at the Pontiac dealer, who confirmed my suspiction - the computer monitors how you drive and adjust the engine performance accordingly.

You see, my GTO is my everyday, to-and-from work car. For me, this means about a 30 minute crawl each way. (Ugh) Oh, there's an occasional time where I get to unleash a few ponies, but much more a droop along with the crowd.

So now on the computer is getting all this data saying "Oh, he like to drive nice and slow, easy does it..." which is alright while I'm in the mist of this, but how do I tell the car, "Okay, its Friday night, we're going out to terroize the race hondas!" ?

The sales guy suggested calling the 800-number roadside assistance and asking to talk to an engineer.... I can here the conversation now: "Um, Ya... Hi, this is Roadside Assistance? Ya well, I'm about to get my doors blown off by this Mustang next to me at the stoplight unless you can tell me how to reset the computer."

Anybody know how many "data points" the computer keeps? If I do X-number of WOT (Wide Open Throttle) take offs, will that give the computer the idea that I'm some mad man that it better wake up and get out of slug-mode?

---Larry
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post #2 of 40 (permalink) Old 09-09-2004, 10:44 AM
 
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Bill Reid might be your man for this one. I will throw out a SWAG anyhow. The sales person at the dealership isn't a technician. Most of the factory technicians I have dealt with over the past ten years here at the dealership don't care how your car performs at WOT. There are some excellent people here in our service department, but performance is not their usually not their game.
I could be way off here, but the car does learn as it is driven. What it learns at a low percentage of throttle opening with a given manifold pressure and MAF reading is only going to adjust the low speed or light throttle part of the map. I can't see that a WOT high load map could be compromised from low speed info. Heck I don't know, I'm just a parts guy!
I do have a buddy with a 99 Firebird (4L60E). He used to drive 40 miles round trip to work and back every day. He raced the car almost every Saturday night and we never noticed any kind of performance issues.
I'm sure that someone will post a reply and set things straight.
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post #3 of 40 (permalink) Old 09-09-2004, 12:23 PM
 
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I just talked to our tune up and driveability tech. He referred to it as "adaptive memory". He felt that the main purpose was to adjust shift points and shift firmness to suit driving conditions. He was not sure of the time frame needed for the ECU to learn or change, but he did say that at WOT the ECU falls back to a fixed timing and fuel map to give you max power regardless of what the car has learned up to that point.
I still think that someone with some chassis dyno experience and something like the LS1 edit program could tell us for sure.

Brian
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post #4 of 40 (permalink) Old 09-09-2004, 03:03 PM Thread Starter
 
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Brian,

Hey, thanks man. You're right, the sales guy isn't technical, but said he did consult a tech. Now, not sure if that meant the order writer from the service dept, or someone that might actually know. He has, on other occasions, gotten information from someone who's title I can't remember now (the memory is the 2nd thing to go... I forget what the 1st is...), but it did seem to be a good source.

A relatively easy thing that Grand National users did was simply disconnect the negative side of the battery, count to 10, then re-connect. Easy to do on race day. That allegedly set things back to their starting point.

It would be interesting to here exactly what the ECU controls when it "learns" and how much variance it is allowed.

---Larry
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post #5 of 40 (permalink) Old 09-09-2004, 03:06 PM Thread Starter
 
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Drat - meant to ask... what is "shift firmness"? What does that mean?
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post #6 of 40 (permalink) Old 09-09-2004, 04:44 PM
 
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Shift firmness is just how hard or soft the trans shifts. On your GN, you had a 200-4R trans that was controlled by a TV (throttle vave) cable hooked to your throttle body. It was a little bit different than the old "kickdown" cable from the 70's. The TV cable was constantly telling the trans what the throttle position was. A combination of that and the trans governor speed told the trans when AND how hard to shift. This was accomplished by raising or lowering the line pressure within the trans. Light throttle and low speed would give you an early soft shift. When you go to a greater throttle opening and/or increase the RPM in a lower gear,the trans would shift later and harder/firmer.
On your Goat, everything is handled with electronics. No more external cable or mechanical governor. It uses the throttle position sensor and vehicle speed sensor to calcutale engine load, then uses the pressure control solenoid and multiple shift solenoids on the valve body to control shift "quality". It's still just a matter of changing and applying line pressure to hit the clutch packs harder or softer, sooner or later.
Sorry for the ramble session.

Brian
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post #7 of 40 (permalink) Old 09-10-2004, 08:24 AM Thread Starter
 
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Oh no, ramble on man! I'm just a computer geek that likes fast cars, but knows only a few details about such workings. I had no idea that "firmness" was something that was controlable. --thanks!!!!

Larry
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post #8 of 40 (permalink) Old 09-10-2004, 04:38 PM
 
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"Adaptablity" is NOT preformance "learning". The ECM does not "remember "how you drive nor does it effect preformance as you know it !!!
The adapt leaning in the ECM software is there to make all vehicles preform the same with regard to shift "firmness", and is in there to account for production variation. The length of the actual shift is measured and internal shift pressures will be "learned" into memory. ( to yeild a given shift time at a given ERPM )The adaptablity is not related to a shift pattern, " how and where the shifts occur with regard to RPM" ( that will remain as programed ) but to make every vehicle "feel" the same for the same throttle input vs. a given ERPM and shift. Hope that helps. I'm not sure I can elaborate further. I know how it works. I will jump in and try to help with technical issues in the future. But what is said on a public forum ( for Me ) will have limitations.
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post #9 of 40 (permalink) Old 09-13-2004, 07:43 PM
 
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its adaptive fuel strategy. if your abuot to go out terorizing hondas just start giving it hell more often before you actually get to terorizing them. it takes a few miles to lean the new driving style. most late model cars have this. it does render performace but not really enough that you will be able to tell.
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post #10 of 40 (permalink) Old 09-13-2004, 08:30 PM
 
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CR125,
The first questions were with regard to shift learning or transmission adapt learning. (Shift point do not adapt nor learn)
What is "learned" in the transmission is line pressures as they releat to shift times, measured by the ECM,and they do not change the shift points vs. Throttle.
Secondly, fuel "learning" does not effect WOT. Fuel learning is feedback control from the O2 sensor to keep the engine at soich during "closed-loop" fuel control. While there is some effect from the learned " adapt" fuel to wide open A/F ratio. ( how you drive does not change what is learned as the fuel map is adapted vs. speed and load. And unles you have NEVER run at a particular speed and load the default value would apply. Other wise the last time that speed and load where encountered the "adapt" is already in memory.It is not ONE memory but many seperate memories that cover the entire engine operating RPM and load range. If you drive easy and did not "learn" a particular speed and load for some length of time, that does not change the last value that was learned. After the initial "learn" of a specific hardware set the adapt values in memory will only change slightly, or until a very different fuel chemistry is used. ie. Calif. Phase II or winter vs. summer blend) The WOT A/F and some other operating modes are NOT closed loop. They are open loop fueling. So for all intents and purposes how you drive and how the fuel adapts "learn" does not effect wide open throttle. The only adapt "learning" that does effect performance, is the knock control portion of the spark control. That is a complex system, however, as long as you have a high enough octane fuel to avoid any detonation, you will have maximum spark. ( Once the system "senses" NO Detonation it does not add more spark if you increase the octane even higher.Above the recommended 92 octane. The Max. spark is set for 92 octane fuel. And any gains that might be realized form a higher octane are moot without a corisponding increase in spark.)
So I stand by my statemant, how you last drove your vehicle does not change the performance with regard to shift speeds or Wide Open A/F ratio.
If you hammer it when it's hot hard enough to start getting detonation, you will have less spark until the knock system "learns" back to the max. spark values in the ECM. But driving "easy" all day, as was the original question" does not need to be "unlearned".
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