A little background. 87 Chevy S-10 Blazer with a 91 vette TPI running ? 91 camaro ECM (7730 AUJP) and wiring harness. The harness is complete except for the ALDL connector. It has the 3 plugs that go in the ECM and an extra plug that I have traced the wires and found to be associated with the ALDL.

The motor runs but has poor acceleration up to 1500 rpm's - then it seems to have all kinds of power.

My problem is that I can't connect with TunerPro RT or any other program to the ECM for data logging. I am using a MaStach cable. It tests out fine and I don't have any serial issues. I also have an Ostrich that I have no issues emulating with. I have just replaced the 7730 ECM with a reman but that didn't help.
My thoughts are ; there is an issue with the MaStach cable.
I'm not using the correct serial wire (orange).
or I'm not using the correct definition file.
Has anyone used this type of harness before, with the extra lead coming from the ecm? Could you shed some light on the correct pinouts?
Can anyone point me towards the correct ALDL def. file?
Is it possible to tune without datalogging?

Thanks in advance for your help.