Flash File Editing/Upload/Downloading.etc

[03_EB_Z06]

I've written software that allows editing of flash files, but now I need to have a look at
obd-II read/writing. The 3rd part and the most difficult I suspect is locating data within the flash files. Can someone point me in the correct place to look at address defintions for tags within the flash files? Mucho appreciated. I'm looking at software + b&b cable + flash files as a way to tune my car and may also off to the public.

Note, a copy of the software (which is basically set up for the FORDs) is here:
http://home.attbi.com/~pabooth/software.html

[Keith@HPTuners]

Hi and welcome to the board.

I checked out your web page, VERY nice job on the software.

Currently there are no maps available publicly for GM OBD-II flash files.. I know of a few people that do have these maps however no matter how much $$$ you throw at them they won't budge.

I started working on a map for a 97 3.8 F-Body but haven't finished it yet.. I basically map out just tables.. however I have to refine it because I mapped out a lot of tables that aren't even used. :-\... haven't defined the tables just yet though.

Regarding the cable.. If you do use a B&B cable you have to write your own loader program as GM's loaders (if borrowed) would overflow the buffer of the cable and most likely produce undesireable results.

[Guest]

As I read the B&B Cable protocol, I thought it was odd that they mentioned only 32byte blocks, then I heard they could do 100bytes per packet. Is there a better cable you would recommend?

Thanks again,

Paul Booth

[Keith@HPTuners]

Hi Paul,

According to my research, the B&B cable is the biggest buffered VPW-RS232 cable out there. In theory it should work for programming with your own loader program.. however it just may be a little bit slower than the traditional tech-2 method.

If you plan to "borrow" GM's loaders, you may need buffers as big as 8092 KB I think.. at least thats what the specs call for if my memory serves me correctly.

A few members on this board were talking about designing a custom cable.. which I believe would be our best bet.. hardware design is something I don't have enough experience right now to contribute to that project. I hope they come up with something though.

- Keith

[RoboGeek]

yea.. I'm trying to eliminate the buffer and have a 'dumb' cable that only translates the communication protocols

The flags and other areas are the hardest to find. Tables are bigger and have a pattern you can see but single bit things are usually well hidden.

Here's what I'm going to be doing once my test bench is functional.

Capture the bin file when all is well.
Trigger the event I want to change (like putting the speedo over the limiter).
Read the bin again and compare it to the previous to see what code changed.
Possibly assemble the code and backwards engineer to find where the specific area needs changed

Hopefully that willl give me a general idea where stuff is. At least I'll know what sensors change what area in the code which is a good start.