Hi, I am trying to do some data logging with my 1989 Firebird V-6 and TunerPro RT. I am using a bought ALDL cable. When I plug the cable in and turn on the car it runs w/ the SES light on. If I hit "Connect" in TunerPro it nearly instantly connects, however no data is transmitted. It appears that it is just saying connected but isn't. Anyone have any ideas?

That ECM, the '7302, uses 160 baud on pin E of the ALDL connector.

Usually the C3 ECMs output the data all of the time. No need for a 10K on A&B. But it looks like it will only output 8 data bytes, where with a 10K will output 25 data bytes. Not sure it that is correct.

Try it with both the 10K on A&B and without the 10K.

RBob.

Thanks RBob.

I am was using this Diagram for the connection:



After playing with it I think it may be the computer. I finally got the cable to test ok about Disabling and Re-enabling the serial port. As soon as I connected it however, it wouldn't test ok. At that point it was late enough I gave up for the night.

The A20.ads I grabbed from Moates.net said in the comments use 10k resister, so that is why I was using it.

So now I am confused. I spent 45 minutes tonight messing with it. What I found is that with the cable unplugged from the ALDL port TunerPro will test and come back with the cable is found and ok. Once I plug it in TunerPro returns that no cable found. If I unplug it from the ALDL port again it still says bad until I restart TunerPro. I am throughly confused on this, I wish I had another laptop to test the 160 buad on or something. I tried DLing a program that will read the raw data off the serial port but that didn't seem to help.

Think it is my laptop, the cable or the cars computer? Any thoughts on narrowing it down?

Not sure where the issue is. IIRC, when TunerPro checks for the cable it sends data and expects it to be echo'd back. This is normal operation as it is a one wire interface (not including ground).

Try WinALDL and see if it does any different. It is a free download from Joby's site. Here is the link:

http://winaldl.joby.se/

RBob.

TunerPro tests for a valid cable by sending a predefined byte string out to the port, and reading back the echo. If the echo matches what was sent, it is assumed that a valid cable is attached (or at least on with tx/rx tied together).

160 baud, as Bob mentions, outputs data all the time. When the cable is connected to the car and the key is on, data is streaming to the PC, filling up the serial buffer. When TunerPro sends the byte string out, the ECM is also "talking on top of" of the echo that TunerPro expects. The echo therefore does not match, and the cable test fails.

Shorter story longer, do the cable test with the key off.

Also, the next version of TunerPro has a much more robust 160 baud connection/acquisition scheme. Oh, and 160 baud is an abomination.

-M