Is there a difference between the pins on the ALDL between the V6 and V8 cars? I've got a conversion car (originally V6, now a V8) that needs tuning and I can't get a connection.

BTW, it's a 1994 OBD-I car.

 

I would have to say no... I did an LT1 swap an used the ALDL ports according to the instructions. I didn't have any software ahead of time to talk to the V6 tho.

 

There are some differences, but the A (ground), M (serial data) and B (diagnostic) terminals are in the same place. If you have done a conversion, you need to make sure the PCM connections are getting to these pins on the DLC.

1994 LT1 PCM

PCM**DLC
D20 -- B
D30 -- M

 

Thanks for the assistance. I'm thinking about pulling out the wiring diagrams and just patching in near the ECM instead of the plug. I *think* the plug may be in upside down (no cover on the plug, just the terminal block), but nothing good ever comes from me trying to "think". I should only need the 3 wires to read, correct? I did connect using Datamaster and did a COM test, but when I tried to read the VIN, it lost COM. Supposedly, there's a Hypercrap program already loaded into the ECM, but that shouldn't affect connections.