Ok, start off by going to ECMtuning and downloading the latest version of ECMlink:
click
I think you mentioned having a MAC, so grab the current stable version (v3.27.92) applicable to your machine.
After you have ECMlink downloaded, install it on your machine. Instructions here:
click
Once it's installed, turn the car on, and plug in your cable to the OBD1 port. Connect to ECMlink via your laptop and grab a log.
Once you have a log, you can email it to me, or post it on a free file upload site and then post the link to it here.
Basically, I need to see how ECMlink is currently configured, and in order to do so, I need a log. Until I know what ECU input is configured for the MAP sensor, I can't help you troubleshoot the circuit. Once I know what ECU input ECMlinkk expects the MAP sensor to be on, I can ID the ECU pin and help you verify the MAP signal is going to where it is supposed to.
If any part of this doesn't make sense, let me know.