Hey guys... Have an issue that I've been chasing for a while now. It is just coming back to the surface however due to the HSR I just installed and the tuning that I need to do. I am using Tunerpro RT for chip changes and ALDL datalogging, but there in lies the problem. I am having issues getting the ALDL to give a continuing information stream. It is not all the time, but when it happens it happens over and over. Basically, I will get the datalogger (have tried more than Tunerpro) hooked up and the ecm connected through the appropriate channels. I will start scanning and viewing the data as it flows, then it will simply stop. It will lock the data in and the connection will be lost. I restart Tunerpro, and try again to connect but most of the time it will not. It gives me an error message that either it failed to initialize the port, or that it could not connect. Now you can see my issue. Sometimes it takes a while before it will connect again. It does not have this issue all the time, but I'd say at least 50% of the time it will lose the connection. Any ideas? The ECM is fairly new, but is an Autozone replacement I put in the car a few years back. The car has probably only 3-4k miles on it since then. Maybe a ALDL ground, or ECM ground? The cable hooks up (Moates cable w/ USB converter) so I don't think its the cable. It has the vertical switch and I had to play w/ that at first to connect, but now it is in the correct spot and works sporadically. Any help is appreciated guys. If you could provide any area's that I need to check that would be great. Also... this also happened when I was using the Auto-Xray a few years back as well. So this is not a new problem from Tunerpro or the cable... __________________

This is common for the 1227165 in your 89. I think just about all of us have experienced it. You might try replacing the ECM. It's a crapshoot. Sometimes you'll get one that does it, sometimes you won't. I took me 3 tries before I came up with an ECM that doesn't do it (a remanufactured unit).

Anyway, it's a common problem. No one is quite sure why it happens.

The issue does not affect any other ECM functionality - just the ALDL stream. So it's anooying, but you can continue to run with it. You need to shut off the key (completely) for ~15 seconds to reset it.

Thanks for the information. I'll keep that in mind and see about getting a unit to swap in and see how it reacts.