Hack and program you own Motronic Chip
 

The rev limiter is located at 130h and is equal to the hexdecimal value*40. For example, looking a location 130h in the screenshot of UltraEdit, you will see it reads A3. Hex to decimal conversion of A3 equals 163. 163*40=6520, the rev limit shown on the fuel map. Want to raise the rev limit to 6800? 6800/40=170. Decimal to hex conversion = AA. Change A3 to AA with your hex editor and save.

UltraEdit32 screenshot
http://www.pelicanparts.com/ultimate...s/ultraedt.gif

Oh great. Just what I need. More ways to play with my car!

Very cool Steve. Thanks for the tip.

And I thought MFI and Webers were fun to tune. This makes it possible without getting dirty and smelling like gas.

Wow, that's pretty wild stuff!

What I find similarly interesting, and maybe a bit more "accessible" to those of us who haven't practiced our hexadecimal conversions and assembler programming in a while, is what you can do on the newer OBD-II Motronic cars.

For instance, for $199 I can get the (laptop) interface cable AND software to view and reprogram all kinds of stuff on my S4. http://www.ross-tech.com/vag-com/index.html

Big brother is here! These little computers keep track of all kinds of stuff...

I don't know about the rest of you but I am impressed.
Good job!

Steve:

You need to get together with Mark Hargett. He also fiddles around with simple, mundane tasks as you do. :)

Mark is working on a "roll your own" "x"-actuated paddle style transmission for his supercharged motor in his 993 look car (the entire car all engineered and all hand assembled by Mark).

Seriously, folks like you and Mark never cease to amaze me - IMO you guys are the Einsteins of 911 performance. It is amazing that a single individual can set out to master skills that once required not only a small team of engineers, but a "factory" to provide support!

Reminds me of the early days of the personal computer. Sheeit, it may take "two guys in a garage" to field the next Porsche Le Mans outright winner.

Although I offer very little to this thread, I applaud you for your work. Very impressive. Time to start thinking about business "arrangements". :)

Best to you,

Kurt

LOL - steve i'm also impressed http://www.pelicanparts.com/support/smileys/clap.gif

i've got an '86, a laptop, enough spare cash, and love to play with stuff for the hell of it (an inquisitive mind)

have you actually tried it on your car yet?

the dickster:D :D :D

OMG, and I thought I was a techno-geek! Very impressive indeed Steve. How did you figure all of that out? Are you a programmer? I have also been playing around recently with electronics and have a project you might be interested in. You should put this together as a package and market it.:eek:

I wish I understood. Looks good though!

god bless you Steve.

Protomotive was selling the same "stuff" ,I think, for $999.00.
http://www.net-quest.com/~knighton/software.htm

Steve, I have a carrera intake manifold complete with injectors and airflow meter.

Question: could i use the Motronic system on a turbocharged engine? Obviously the software would have to sense pressure? Ideas?

Where does one get the reader/writer and extra chips?

TIA

It strikes me that it wouldn't be too hard to build a nice graphical front end to perform the re-maps under the covers! Then talk to the eprom writer and you would be in business! Make it open source, and free...all the better!

Matt

350hp SAAB hehehe.....great stuff....

It looks like I'm going to be keeping my eye open for a motronics brain.

Keep up the good work.

steve - you know about hotwire as well! is that the same as hotfilm?

i'm hoping to upgrade to that (hotfilm) eventually (money!!), sounds like you think its worthwhile.

the system i'm interested in is by amd (uk firm). theirs uses an interface that converts the signals to talk to the cars computer. they also told me that there is no cutting of wires involved, plugs right into std harness.

i'd be real interested in your comments

the dickster:D :D :D

Here's how you convert values in the idle, midrange and full-throttle Fuel (lambda) tables to something readable.

Lambda trim = value / 127

Hokay-Hokay

Would a practicle application of this be to backdate an early SC that had CIS with a motronic unit? Thus build the hot rod and still take it to the emission testers at inspection time?

Enquiring minds sometimes ask those that know.

Thanks,
David Duffield

While updating to Motronic would make things more tuneable and efficient, the necessity of running a mild cam would still remain. The air meters on both these systems don't like to see pulses coming back up the intake from a more radical cam.
-Chris

How about adding a bit of code to utilize a knock sensor to retard ignition timing ... or maybe retrofit a 964 DME unit, and make its' fuel timing values programmable for different-sized engines and varying gasoline quality?

The fuel tables are actually trim values in lambda. The base injector pulse width is determined by the air meter signal and RPM. In fact the data points (x/y) for the 3d fuel tables are rpm and base injector time.

There are also trims for air and engine temp as well as a host of other things like cranking and warm-up.

Also, there's a really important often over-looked ignition trim based on intake air temp.

-doug

Spill it Doug! How do you know so much about this? :D
-Chris

Hours and hours of reverse engineering using an 8051 emulator. I turbocharged a 964 which required larger injectors, a pressure sensor and a hot film air meter.


-doug

Sounds interesting. Please tell us more like how fast, how powerful, how reliable and how much. All this motronic editor stuff is very interesting but would it not be more cost effective to just go with a unichip? They can be retuned very easily too and all the installers have dynos so that saves a lot of guess work and gas during tuning.

Well where's the fun in that? :D :D

Impressive. I've just started on this journey except with the earlier '84-89 DMEs. I'm just using a software emulator and a disassembler.
Did you use/do I need an in-circuit emulator?
Did you tease out the formula just from the code or are there references that you could direct me to on Bosch DME theory/formulas? I've managed to find a little bit looking at some old posts to the DIY_EFI list.

thanks in advance,
Chris
chris@a3ds.com

I havent delved too deep into this but I wonder how difficult it would be to take all this info and turn it into (x-)*nix capable software.

SMOB

PS-Pay no attention to the 'Senior Member' title underneath my name...with little effort anyone can get that ;-).

Chris,

I used a disassembler and a freeware software emulator. I also have a very handy EPROM emulator and a wide-band 02 sensor.
There's no one place to get this information really. There are a few good books on theory--DIY_EFI site has a list--but nothing that'll tell you how to tune the IAC pilot control. My favorite books are the Bosch "Red" book and the little yellow Bosch "pamphlets."

I wrote a Motronic table editor that does a decent job at displaying values in readable form. It requires some skill to configure--you need to determine the addresses of the tables you want to edit--You're welcome to a copy of it.

-doug

I think it would take a lot of effort & info to turn this into a usable piece of software. The more you look into it, the more you'll see how little info we actually have. Basically most of what you've seen was obtained by using Protomotive's DME editor (distrial.exe).
I'm working on this for fun but I have no allusions that if I could edit the DME software that I would be able to a good job of tuning my car with it. After all, years of writing CAD/CAM software hasn't made me a mechanical engineer. :rolleyes:
Chris

The hot film meters require 12 volts, the flapper uses 5 volts. You can make a small wiring change at the DME connector to provide 12 volts. You have to add an air temp sensor too. There's one built in to the flapper meter.

On the EPROM there's a "air flow meter transform" table that has to be redone to match the new air meter curve. This is the tricky part and I could never explain it in one e-mail. The response curve of the hot film meter looks a lot different from the flapper and can not be done correctly with the existing code so you really have to re-write some code to make it work well.

There's an air-temp compensation table that has to be "flattened." You don't need air-temp compensation for fuel because the fot film meter is measuring air mass flow.

The newer Motronics with diagnostics require a bit of effort to prevent the new air meter signal from setting error codes but I don't think this is an issue with the '89 and earlier ones.

The fuel tables are for fine-tuning. If the air flow meter transform function is done right, the fuel tables will not require much work to get the car running well.

Reprogramming Motronic for different injector flow-rates is a real pain, especially on the 964 and newer cars. What makes it so difficult is that Motronic uses injector pulse-width to represent load so injector pulse-width is referenced in a lot of places.

-doug

Something a little better to put in here.

I found a site that has directions for building an eprom reader for 5 bucks:

http://www.zws.com/products/epromr1/index.html

Anyone care to comment?

SMOB

Steve M,
The '84-89 units I've seen have used 3 flavors of Eproms:
2716 (2Kbytes), 2732 (4Kbytes) and 27C64 (8K bytes).
The latter one is used in '89 for sure and probably late '87 on.
One of the readers they have will do 2764's but according to them you could modify their circuit to work with smaller Eproms.
-Chris

... and what about a Real-Time EPROM emulator connected to a laptop and you can do modifications to the values in real time... see here --> http://space.tin.it/computer/lorgler/nonst-e.htm or here --> http://www.racelogic.co.uk/emulator.htm

Normal EPROM emulators start at around US $150.00

I have use some of the emulators to debug/modify/customize some of my home video/audio stuff (my other hobby), never for my car (the most advanced electronics are a couple of relays)

Just a wild thought..

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drb930, you realize this thread is over 7 years old since the last reply, right??