All,<p>Thanks for the comments on the (part 2) posting, for those that are curious, it's down the list somewhere.<p>I wanted to clear up a few things that look to be springing up from that post.<p>1) As it relates to the "learned" tables or the tables that have been changed with "adaptation". They are stored in a RAM memory location (I'm not sure if this is in the 87C196KR processor or in a custom chip, but it's somewhere different from the flash). They retain their "learned" values and are tweaked as needed either up or down (maybe you ran some really high octane fuel and the ECU decided it could add a little more timing) through life until one of two things happen; a) You run down the cars battery, but it would have to be completely dead, or you disconnect the battery. b) you unhook the ECU to replace it or change the chip.<p>Once that happens the tables are reloaded with defaults from the flash values and the "learning" process starts over again.<p>2) On the topic of programming the ECU without removing the chip. There are some pitfalls with this mechanism. It's not just as simple as hooking up a connector to the ECU and "flashing a new program with tables". Think about what's going on. The little black box is really a PC in generic terms with all the peripherals that the PC you are using has. In fact a few more, there is a serial port, a bunch of input/output pins, timers, etc. Just like you couldn't flash your BIOS (a very good analogy for the flash in the ECU), when your PC isn't running, you can't flash the storage in the ECU.<p>Once you have your PC on and DOS is running you can flash your BIOS. Similarly, there is protocol that is part of the OBDII support in the ECU that knows how to take a "flash" image and write it to the "flash eprom", but the 87C196 has to do that work, because there is no direct way to get to the flash from the connector directly to the flash eprom. Now before you go thinking about the catch 22 with that statement (wiping out the instructions that the ECU is using to know how to support the protocal with a "new flash image"), you have to understand that there is a small amount of One-time-programmable (OTP) memory in the 87C196. Usually this is where a basic routing is to keep the system running while a flash update is occuring. Those instructions can't be changed, hence the One-Time-Programming statement, unless the processor if physically swapped out. More to the point as to why this method isn't used. <p>Usually an engineer will create a double buffer scheme where he will take the "new image", save it to RAM somewhere, erase the flash eprom, and write the new image out to flash. There is a slight chance that if a glitch happend while you were "flashing the part" in a software mechanism, you would render the ECU brain dead and there isn't enough intellegence to get it back started again. You'd have to remove the part and reflash it the hardware way to resolve this problem. Usually this isn't a problem for car companies. They don't give us the tools to do a software upgrade. But it can happen. How many of you have had this problem with a 56K upgrade on a modem? :-). BUT, it is being done, and I got a note with information that Garrett Lim can use this mechanism.<p>The biggest reason most aren't using this is because they haven't figured out the protocol or don't want to deal with the issue I mentioned above.<p>Couple of final pointers. While, yes, you can, unhook your ECU and let it set and then rehook it back up and start the learing process all over again. Just remember, if you take your car in for service, the dealer can tell that you've done this. The ECU can determine if power has been removed, or if external sensor like the Throttle body have been what it thinks is intermittent and it will set a code. Those code are not cleared with a power cycle. Also there is a ECU "adaptation" code that needs to be valid and it's wipped out on each power cycle, it will relearn it, but that take more that just a single or even a handful of engine starts.<p>Ok, there you have it, round 3. Hope this is helpful. I only wish I had the software so that I could go tweak my tables directly... Oh, well, maybe some will send me an annonymous email with sw attached! :-><p>Alan

In dealing with Ned Ritchie of Intended Acceleration, he mentioned that if you get a bad batch of gas, in which the ECU needs to significantly detune the car to run, it can take up to 50 starts (on/off cycles) with "good" gas to get back to the original performance levels.<p>I had this happen once, and just unplugged the ECU to allow it to clear. <p>On the other hand, I have noticed that my car tends to feel a lot more peppy immediately after a track day or a couple of autoX runs - the turbo sounds like a swarm of bees :-)<p>Dwayne<br>94 S4 (no bees till spring)

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Hmm.. you have the tables.. I'll get the software.. ;-)<p>Seriously, I think that Garrett will be the way to go for me. I was going to go Wett just because they're based closer to Chicago and I would have driven there to get it done. When is Garrett offering the "flash" w/o chip replacement option? Where does he live? I'd like to do a custom tune if I could. What are his torque levels set at and at what speed/rpm does it peak? I'll check his site for a graph, if one's out there. Also, what will he charge for this 1.0 or 1.1 bar flash update? Feel free to offline e-mail me if this is off-topic..but I would think others may be interested in this option if it were offered.<p>Anxious for information -<p>Kevin<br>99.5 1.8tqms (May)

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