Build a Subaru Select Monitor!

[longassname]

it's at a 2048 clock which is not close to any standard uart divisor. In linux the serial port hardware can be accessed directly but in windows you are sending a call to the os to access the serial port and telling it the baud rate with each packet. The os then selects the closest integer divisor to approximate that baud rate. C++ would be the language of choice to write the software in but I wouldn't get my hopes up too much for someone to write it for you for free. There is a lot more to be done beyond being able to communicate with the ecu. You aren't talking about accessing obdII data you are talking about direct memory reads which means you have to know what is stored where in memory or you are just looking at a bunch of 1's and zeros. This is why the select monitor uses cartridges. Despite similiarities in the software between models and the software being put together from the same source code modules after compiling into the processor specific machine code the locations in memory where things are stored are always different. Each and every model of subaru has different data stored at different addresses.

[McTaff]

Originally Posted by UberRoo

I have no idea which season is which, but I think that's from the backwards episode. I believe the line was, "Don't ask."

Winnar!!!

Originally Posted by longassname

-I'mSmarterThanMcTaff-

Wow. Just reading that made my head hurt.

Next questions:
1) Is it worth it, or is there an aftermarket accessory which will do the same that you can buy pretty much off the shelf?
2) What exactly is the end product you could get with this if we really could get it to work? What are the implications/advantages/applications?

I think the only thing here that is selling me on it is the fact that I could use a laptop while out-and-about to access the data. After all, if I was worried, I'd just take it to the Subaru dealership, or a tuning shop...

[MaxImUmZ]

Hello, CS student with WAY too much time on my hands.... it sounds like a monumental task but one that is do-able and Id be willing to take on once I got back to school. Might make for something cool to show off to future employers.

[floatingkiwi]

Wasn't ECUTune going to do something like this for a while? LAN? no more plans for this?

Matt

[b3lha]

Originally Posted by longassname

it's at a 2048 clock which is not close to any standard uart divisor. In linux the serial port hardware can be accessed directly but in windows you are sending a call to the os to access the serial port and telling it the baud rate with each packet. The os then selects the closest integer divisor to approximate that baud rate. C++ would be the language of choice to write the software in but I wouldn't get my hopes up too much for someone to write it for you for free. There is a lot more to be done beyond being able to communicate with the ecu. You aren't talking about accessing obdII data you are talking about direct memory reads which means you have to know what is stored where in memory or you are just looking at a bunch of 1's and zeros. This is why the select monitor uses cartridges. Despite similiarities in the software between models and the software being put together from the same source code modules after compiling into the processor specific machine code the locations in memory where things are stored are always different. Each and every model of subaru has different data stored at different addresses.

If the addresses are different as you say, it will be a painstaking task to figure out what is stored at each location.

But, if the source code contains some of the same include headers (which would be a reasonable assumption) then the position of the variables within each struct will be the same - even if the struct is located somewhere else on the heap. The information on the original webpage can be used as a starting point.

Then it's a matter of dumping the memory contents, changing a single input, dumping again and diffing the files to see what has changed in the memory. Then doing it again and again and again, gradually narrowing it down and trying to work out what's where.

When I was a student, I spent many many hours reverse engineering. I would love to do this as a project, but I don't have the time to devote to it anymore. If MaxImUmZ does it and writes then I'd be happy to send him a few dollars in recognition of what I know will be a lot of hard work.

I know that you have already reverse engineered the ECU and you have figured out what's in each location. I respect that you could not give that knowledge away. After all, it's what makes you the king of SVX tuning. Maybe once the supercharger project is finished, could you build and sell an SVX monitor? Just the converter circuit, and a knoppix CD with some custom software? Maybe you could employ "a CS student with way too much time on his hands" to do the development for you? Or give him the info under a non-disclosure agreement, let him write the software and take a percentage of the sales?

[MaxImUmZ]

Originally Posted by b3lha

I know that you have already reverse engineered the ECU and I respect that you could not give that knowledge away. After all, it's what makes you the king of SVX tuning. Maybe once the supercharger project is finished, could you build and sell an SVX monitor? Just the converter circuit, and a knoppix CD with some custom software? Maybe you could employ "a CS student with way too much time on his hands" to do the development for you?

Will work for beer

[Cappy]

I'm thinking of buying a select monitor that comes with cartridges for a1992 SVX Lsi, AND a 1996 SVX as well. My car is a 1994 SVX Lsi. Is there much likelihood that either of these cartridges will work for me? If not, can they be purchased anywhere, or are they no longer available for a '94? Any leads?
Thanks,
Cappy

[mohrds]

Originally Posted by ssnsltd

Some do some don't.

I have my dive computers I download via RS232, took awile to find a USB to RS232 that worked for data biderectional transfer.. RatShack has one that works with any RS232 device.

I have several of the RS adapters and I have yet to find a serial device that doesn't perform flawlessly on it. I've used it to communicate with routers, modems, home automation gear, robotics gear, UPS, etc and it always works.

Doug

[Jade Dragon]

Originally Posted by floatingkiwi

Wasn't ECUTune going to do something like this for a while? LAN? no more plans for this?

Matt

i remember reading this too. dont remember where though. i have done this before, and it was a royal pain in my ass. but thats also because the software ran in dos mode, and i dont like the look of it. If someone were to make a computer based app, please make it windows based, i would like to be able to store data and what not.

[Beav]

Considerations:

Do any of you know what to exactly expect when using a monitor? Now don't get me wrong, I'm not saying anyone isn't intelligent enough. But a lot of people think there is something magic about the info they provide and that just ain't the deal. That's like thinking there's some magic phrase that will get you 80% off at the hotel or make the waitress rip her blouse off in front of you and your buds.

OBDII cars require them to retrieve codes but codes don't necessarily mean squat. You'll still need to use other stuff -a DVOM is absolutely requisite. O.K., there is one point access to a lot of sensor info and the misfire monitor, etc. - all good stuff. How many of you have OBDII cars? If you do you can get a generic OBDII scanner for $139 that will link to your pc, here: injectoclean.com

OBDI (a misnomer, I know) codes can be flashed on the dash, so what is the scanner good for? If you haven't caught on by now, codes don't mean diddly on their own. You will still need to investigate the system involved in the displayed code in order to repair the problem. No misfire monitors on OBDI. The only other info of real use that isn't available by sensor would be fuel trims but they aren't so important for diagnosis that you can't live without them. Any info available through a scanner port is also available with a DVOM at the sensor or at the appropriate wire at the ECU. So you gain a little ease of access. And that is it. You still need how to decipher the info and look for the root cause of a problem.

BTW - the info from a scanner is sent by the ECU. When the ECU gets busy guess what the first overhead to get dumped is? Yep, YOU and the scanner! SO, just when the action gets hot it gets busy and you don't see what's happening! To be honest, yeah, I grab the scanner when walking out to a car but it isn't the tool I have in my hand by the time I'm done. My workbench pc normally has 15-18 windows open all day, the scanner spends most of its time in the drawer and my DVOM is always on the bench, under a hood or on my cart.

If you want to build something of true use how about a DVOM/graphing meter adaptor for a pc/laptop? Everyone will get a heckuva lot more mileage from that - I'd even be up for it! There are a lot available for free but their sampling and display rates are horribly slow. Pico scope is the current leader but it has a lot of unecessary fluff included.

[mohrds]

Originally Posted by Beav

If you want to build something of true use how about a DVOM/graphing meter adaptor for a pc/laptop? Everyone will get a heckuva lot more mileage from that - I'd even be up for it! There are a lot available for free but their sampling and display rates are horribly slow. Pico scope is the current leader but it has a lot of unecessary fluff included.

I have a Protek 506 with RS232 data logging. How fast does the sampling rate need to be to be useful? The 506 does 250ms or 4 samples/sec.

[green_eyed_lady]

If anyone is interested in purchasing the genuine article, bidding ends in about 3 hours (8:26 p.m. EDT) for this one on eBay. It has a bunch of cartridges with it, including the 92 & 96 SVX, according to the description.