bytor
Well-Known Member
I have been getting familiar with the old school ODBI 1227165 ECU on my 87 Corvette. Did some research on what PC based scan software was a good fit and decided to use TunerPro5 with a ALDL to USB cable from these guys. http://www.aldlcable.com/ It took me some time getting the ECU to talk to the PC at the higher speed baud rate (8192). The 1227165 in 87 was a transition unit that could communicate at both 160 and 8192 baud. To start the data streaming, you must place a 10K resistor across A-B of the ALDL connector. My USB cable has a jumper for this that makes it easy. Once this is done, the ECU will start streaming a subset of data at 160 baud. You have to tell it to switch over to 8192 baud. The ECU will transmit at 160 baud stopping briefly to ‘listen’ for commands from the scan tool/PC. If it receives the correct command sequence it will switch over to 8192 baud. It took me a bit of time to figure out how to get TunerPro to send this code. After some research, I have it working. What got me going on the right track was choosing the correct .xdf (ECU bin file definitions) and .adx (data stream definition) files. In my case, I was attempting to use the $32 mask files and they worked fine at 160 baud but not 8192. I found a recommendation to use the $6E mask files. These files had the foundation for sending the commands to the ECU but I still could not get it to work. The missing link was the ‘listen for silence’ command in TunerPro. Once I added this to the mix, it works like a champ. Here's the detail on how to set up the definition file in TunerPro.
1. Load the 1227165 $6E mask in TunerPro by selecting it in the menu Acquisition > Load definition file menu.
2. The edit it by selecting menu Acquisition > Edit definition
3. Under the ADX Header Data expand the ‘Commands’ heading to list the commands/macros.
This is where the command to start the 8192 baud communications reside.
4. We need to add the missing ‘listen for silence’ command. This will cause TunerPro to listen to the serial data stream and as soon as the ECU stops
transmitting temporally, TunerPro will transmit the command to switch over to 8192.
Here’s a screen shot of how to setup the wait for wait time command.
5. Here’s the command that causes the ECU to switch over to 8192.
6. Here’s the command the listens for the response from the ECU
7. Here we take the three commands listen for silence, send command and listen for response and add them to a macro.
The macro is executed once the initial serial communications connection is established between the PC and ECU.
Here’s the overall connect sequence.
1. Connect the ALDL cable with the 10K resistor in place to the ALDL connector and PC.
2. Start TunerPro.
3. Turn the car key on ACC
4. Click the connect icon in TunerPro. TunerPro will connect, run the macro and start monitoring the ECU stream at 8192 baud.
5. You can now remove the 10K resistor to put the ECU in normal run mode.
6. Start the car, start logging and go for a ride...
I couldn't find a clear cut description of how to set this up and had to piece it together. It was a good learning experience. I hope other beginners find it helpful.
This generation of GM ECU's are interesting. It's amazing how simple the processor, code and electronics is with these things. GM had a clue to what they were doing. Obviously, the modern ECU's will run rings around the older ones and monitor hundreds of data points instead of 64.
Interesting links:
http://home.earthlink.net/~cliff_harris/1227165/index.html Good source for 1227165 schematic and ECU waveform details.
http://www.ws6transam.org/aldl_35.html ECU serial datastream details.
http://www.tunerpro.net/downloadBinDefs.htm
http://forum.tunerpro.net/viewtopic.php?t=2215
http://www.thirdgen.org/techboard/diy-prom/581532-tips-hint-how-connect.html
1. Load the 1227165 $6E mask in TunerPro by selecting it in the menu Acquisition > Load definition file menu.
2. The edit it by selecting menu Acquisition > Edit definition
3. Under the ADX Header Data expand the ‘Commands’ heading to list the commands/macros.
This is where the command to start the 8192 baud communications reside.
4. We need to add the missing ‘listen for silence’ command. This will cause TunerPro to listen to the serial data stream and as soon as the ECU stops
transmitting temporally, TunerPro will transmit the command to switch over to 8192.
Here’s a screen shot of how to setup the wait for wait time command.
5. Here’s the command that causes the ECU to switch over to 8192.
6. Here’s the command the listens for the response from the ECU
7. Here we take the three commands listen for silence, send command and listen for response and add them to a macro.
The macro is executed once the initial serial communications connection is established between the PC and ECU.
Here’s the overall connect sequence.
1. Connect the ALDL cable with the 10K resistor in place to the ALDL connector and PC.
2. Start TunerPro.
3. Turn the car key on ACC
4. Click the connect icon in TunerPro. TunerPro will connect, run the macro and start monitoring the ECU stream at 8192 baud.
5. You can now remove the 10K resistor to put the ECU in normal run mode.
6. Start the car, start logging and go for a ride...
I couldn't find a clear cut description of how to set this up and had to piece it together. It was a good learning experience. I hope other beginners find it helpful.
This generation of GM ECU's are interesting. It's amazing how simple the processor, code and electronics is with these things. GM had a clue to what they were doing. Obviously, the modern ECU's will run rings around the older ones and monitor hundreds of data points instead of 64.
Interesting links:
http://home.earthlink.net/~cliff_harris/1227165/index.html Good source for 1227165 schematic and ECU waveform details.
http://www.ws6transam.org/aldl_35.html ECU serial datastream details.
http://www.tunerpro.net/downloadBinDefs.htm
http://forum.tunerpro.net/viewtopic.php?t=2215
http://www.thirdgen.org/techboard/diy-prom/581532-tips-hint-how-connect.html
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