You probably wired it wrong. I recently hardwired a maft into my 1g harness. I also came from a 2g mas. However, I didn't have to hardwire the GM Maf since I had the plug coming from the maft. You will only hook up 5 of the 7 wires coming from the 1g harness. Just tape or cap off the 2 unused wires. Be sure to set the dip switches to the correct positions before starting the car. Also, "zero" out all the dials since you aren't tuning with the maft. Make sure you connect the red wire from the harness to the pink wire on the maft (12 volts). You will not need to hook up the purple wire or white wire coming from the maft. Check out the links below for more help.
Use this for the 1g mas harness colors.
1G to 2G MAF Upgrade chart
Maft version 2.00+ instructions/tuning guide
MAFT Version 2.0+ Tuning Guide - Full Throttle Speed Tech Support
Maft version 1.3 instructions/tuning guide
MAFT instructions, version 1.3 OLD VERSION - Full Throttle Speed Tech Support