Perry 951

Has anyone heard of a real time data logger for the stock Motronics? I am wanting something similar to VAG-COM for the VEE DUBS so I can see knock, ignition advance, etc.

Please post if you know of anything.

TT

I haven't seen anything commercially available but I've recently been working on getting data out of the 944/951 Motronic. It outputs a serial data stream to pin A of the test plug (on US cars). I should finish determining what data is transferred by the end of this week. Initially looking at the Motronic code it will output, at a minimum, values for RPM and ignition timing. Water temperature and a value based on injector pulse width (not the load calculation) can also be transmitted, but I need to verify the conditions under which these values are sent.

It looks like Bosch had put in the capability of actively querying Motronic for running parameters, but the jumper which connects the receive line of the micro to the outside world is not present in the 944/951 DMEs.

I can give you an update on my findings if you are interested.

Perry 951

Please do. Thanks a lot!

Dare

I'm interested as well.

Alan C.

Perry,
How about an hour glass and a note pad? That should work until you get back on the road <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />

TaboII

TT

Unbelievable timing. I just posted and idea I had for adding a computer cheaply in the cars what a match this kind of thing would be. Running data recorded and real time display of information to the driver!!! We should talk! <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

scular

Once it is known what wires do what, it should be possible to hook up an apexi, palmpilot, or a laptop, like on the japanese cars. I am sending a friend, who is PPTRacing.com, an email now to see if he could help setup up a data logger.

Perry 951

[quote] Perry,
How about an hour glass and a note pad? That should work until you get back on the road <hr></blockquote>

I tried that. The bits the computer uses to do it's thing are too small and too numerous to count.

If you only knew how many hour glasses I have flipped, and how many notepads I have gone through!! Jeez.. hey.. watch out.. you had help. I could fire some one liners back at 'cha.. although it might not be that easy! <img src="graemlins/oops.gif" border="0" alt="[oops]" />

You find that rod nut?

TT

OK, I looked at the output tonight and here are the results.

When the ignition switch is turned on to the point before the starter is engaged, the DME outputs a serial byte stream with the data 0xFF. During this time it is waiting to receive a byte, either 0xEE or 0xFF. Unfortunately the 944/951 DME never receives this byte so on starting (after ten flywheel teeth go by) the DME sets a flag indicating nothing was seen and never to talk again.

I modified the code to ignore the flag and output the RPM value to the serial transmit port. I saw the data on the test port. My next test is going to be to connect the test port output to a development board I have using a voltage divider and collecting the data. Fortunately the serial routines in Motronic are in the EPROM area of the 24-pin DMEs so both types of DMEs can be equipped to output the data serially. I will post more results as I get them.

TaboII: I already have an embedded system for modifying the running parameters and code in Motronic. I am trying to close the loop and get operational calculations back out. I've been using the system to do my investigations: modify code, upload to the embedded system, start the car and check the outputs.

Perry 951

Sounds like things are coming along. Can you tell what parameters rest in the e-prom area? Any idea what we will need to have to re-write the code?

Hans

[quote] what parameters rest in the e-prom area <hr></blockquote>Maybe this helps

<a href="http://forums.pelicanparts.com/showthread.php?s=7cd377a0a9c076d9b71693e546bbd7d9&threadid=59861&perpage =20&pagenumber=1" target="_blank">http://forums.pelicanparts.com/showthread.php?s=7cd377a0a9c076d9b71693e546bbd7d9&threadid=59861&perpage =20&pagenumber=1</a>

Please let us know how this works out.
Looking for this kind of diagnosing tool.
TakeCare

Sasha

What kind of embedded system are your running? Is the serial communcation RS-232 or its flawor?

Can one connect standard PC serial port and a terminal emulator program (VT100 or similar) to read and write codes? Or am I way off?

I am intersted in reading data real time out, not modifying parameters. Surely, keep us posted. Once you are able to query it, do you know to format of the output?

Thanks...

TT

The embedded system is one of my own design. I'm working on the second generation which is why I want to get data back out of Motronic and incorporate it into the new design. The comms for my board is RS-232. I have my own comm protocol for transferring data to and from the embedded system. I use a PC based laptop and a Windows program I wrote to control it. I could put a tty control interface in the embedded system but everyone loves GUIs. The current prototype can save and load 8 4k or 4 8K EPROM images. The second generation board will double that.

The Motronic serial output is basically the 8051 serial transmitter run through a transistor to bump up the voltage from 5V to 12V. I have to check if the logic is being inverted because of the transistor. The data rate according to what is set in the code should be 6MHz/64 = 93750 b/s. The data format is 9-bit with 1 start and 1 stop bit. The contents of the data will be whatever I program Motronic to output. Most everything is byte oriented and I have the conversion formulas to make sense of it.

Current status is I have the voltage clamp circuit complete and wired to my development board. I am coding up a test program, will test it, install the thing in the car and see what comes out.

TT

Been awhile, but I finally got around to completing my testing last weekend. I wired up and programmed my dev board and plugged it into the test port in my 88 944 (this will work with the 924S/944/951 cars). I also reprogrammed the DME chip to output the data I wanted to monitor. The Windows program I wrote reads the data from the dev board via a standard serial port running at 115.2k.

Here are some screen shots of the system during various stages of engine operation. For the ignition display the black line is the point where the plug is fired and the red line indicates where the coil starts charging.

Starting:



Idle:



Idle with A/C on:



Part throttle:



WOT:



I will probably add injector pulse width to the info so I can display duty cycle.

Bottom line is this is doable if anyone is interested.

TaboII

NExt question,

Are you going to share the wealth or are you going to sell it???

I want to install this into a car possibly as a replacement to the current gauges. Let me know via email what you plan to do with this. I really want it if you ware willing to part with it. I may even be able to help you with the windows interface as I am a programmer and know many others that can help.

Also how much more information aside from injector timing can you get from the DME and where are you getting the water temp from???
Thanks

TaboII
<img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />