Ok, but how does it actually WORK?!?
 

Ok, I have read threads all over this forum, at Romraider, injector dynamics and other places.
Watched videos on youtube, Haltech, etc.

They all explain small pieces of how to tune: Enrichment tables, MAF adjust, VE, timing advance, knock correction, VVT, etc.

However I cannot find even ONE example of how the ECU actually WORKS!
(and I dont mean: Microcontroller programming 101 - I got that)

In my business there is always a "Systems Engineering Report" that explains whole systems or various subsystems in extreme detail.

For example: Where is the equation that gives the final timing advance?
e.g.: Final_Timing = Base_timing + Table1 + Table2 + Learn_value1 - Knock_correction - Learn_value2 +/- etc, etc.
And I know there are also flow-charts and state-diagrams that are required to understand all of this.
An example state-diagram chart might be: "How the ECU transitions between OL & CL"

I would expect that most of the tuners out there have a good idea of how it works, but where is it explained on paper?

When I open a ROM in Romraider, there are very good explanations of each table/parameter, but you have to open one table at a time and read the explanation.
There is not even a list of: "Here are the most important timing tables/parameters in order of importance"

It seems the only way to learn this stuff is to just randomly click on tables and read the explanation while slowly trying to understand how each table is related to other tables.
It is kind of like putting together a jigsaw puzzle without the picture on the box...

Any books or obscure threads that give a better explanation?:bonk:
I found the Online Toyota technical reference website, but you need to pay to access any data, so I dont know if what I am looking for is even there.

:thanks:

https://sites.google.com/site/asubie...gguide/ver-1-0

It's not for this ECU, but will give you a better idea.

This is why tuners are paid a lot of money to tune cars ;)

It's learned through either trial and error, hours upon hours of studying maps and research, or direct training through classes or shadowing another tuner.

There is a small community of educated Opensource tuners who will share info, but you would be hard pressed to find an experienced tuner to just sit there and teach you how to tune. There are some good resources out there though, as posted above. Get reading for lots of reading!

Thanks for the responses! The link above is perfect!

I understand that. But I am positive that somewhere there is a software description document for how the ECU manages the engine. If Toyota hires a new engine management engineer, I am sure they just dont tell him to go look over the shoulder of one of the other engineers. I am guessing that the info is considered proprietary and even toyota mechanics are only given the information on a need-to-know basis.

I "tune" spacecraft for a living so I get how information must be held as proprietary (I could tell you all about it but then I'd have to shoot you ;-)
That is where I got my ECU/CPU & Software experience, but my "vehicles" are sometimes worth a Billion dollars each:D

i think what you're looking for is like an architecture diagram, which you aren't going to get unless the manufacturer decides to give you one (yeah right!). the info is all out there ready to be consumed, but no one has gone through the trouble of aggregating it all and making it easy on you. google is your friend.

Yeah, the manufacturers go to great lengths to not only keep that info secret, but try and mske their ECU's "unbreakable" so that tuners can't get ahold of it and modify it.

I'll keep you in mind for Spacecraft tuning, I hear some shuttles just got retired and may be on the used market soon :)

OOh some fun reading material for the commute home tonight! :thanks:

Meh.. there's a TON of "here's how this piece works."

This would be a good place to start.
http://romraider.com/forum/viewforum.php?f=15

Way back in the day the actual software code was written in a language like C. Over the past 10-15 years everything has moved towards Matlab. So basically, somebody inside Toyota or Subaru or whoever writes Matlab code. Then it eventually turns into a .bin or .s19 binary file (depending on the instruction set) with a .a2l description of the various tables and maps. This is analogous to what you have with ECUFlash, Rom Raider, etc with the raw ECU file and a .xml to define certain maps. Except if you work for the OEM and have the right security clearance, you can literally see every single entire map and RAM value in the ECU. That doesn't mean you know what to do with it though.

In my experience, Japanese companies are especially secretive about their control logic. They don't leave very good documentation and concentrate it in the minds of a core group of team members. Remember that there is limited turnover in Japanese companies so they can count on those individuals sticking around for a while.

American companies are more "process oriented" i.e., some managers think they can make the engineers "replaceable" by documenting how the ECU works and how to tune it. The work is also more divided up--you might have a cold start tuner, a throttle mapping tuner, a spark tuner, etc. This works fine for carryover engine technology (sticking some existing engine in a new vehicle). New code and methods have to be made up for advanced projects and can't be done by someone with no experience.

Even when you can see the actual block diagrams spit out from Matlab, it's not entirely intuitive to look at. It's more of reference material if you need to look at how changing some value might affect something else.

Not that hard pressed :)

Sounds just like how we build applications in matlab or labview in the development environment and get the bugs out, then we turn it into an *.exe file before releasing it to the "production" environment.

In my business (we sell software solutions to defense & NASA), the software development MUST follow software processes defined by ISO and DOD. We MUST document everything and requirements are meticulously defined & tested. So we cannot do anything without the proper documentation. So I bet the documentation is out there, but even if you had the Toyota FA20 SVDD (Software version description document), you would not make that public or you could get in trouble from Toyota.

Does anyone here have access to the Toyota Technical Information System (TIS)?

It would be interesting to know what documentation is available for training.

https://techinfo.toyota.com/techInfo...M20S0U%2Fxhtml

:bow:
A vacation to SF would be awesome. hmmm..... My wife has been wanting to see NAPA & the redwoods....
Maybe a BRZ roadtrip is in order...:burnrubber:

Interesting find. It looks like Joe Schmoe can buy a 2 day subscription for $55 and get access to TechStream w/ ECU flashing functionality and the latest ECU rom's from toyota. Might be a good alternative for those of you that want the updated maps but don't want an aftermarket reflash.

I am shocked to hear that the ecu is running essentially matlab code. Do you have a link for more information on this?