86/87 ECM swap, Big problems

[camaro75racer]

Ok, finally got everything to swap the ecm over from the 85 to the 86/87 and changed everything over.(MAT install kit and sensor,87 ecm,87 MAF, and both chips one of which is a Thrasher 92 chip) Once everything was changed over the car idled rough and gave no codes. My scanner (one of the ACTRON's) read that it was constantly lean instead of cycling between LEAN/RICH like it's supposed to. After a couple minutes the O2's drop to zero and stay there. After this the car begins to cut out at 2000rpm to the point of the motor dying. Whats up with this? Swapped the computers back out and car runs great with 85 ecm and 87 MAF installed and O2's are normal. Please help.
Thanks
Dale

 

[GNeric]

The Thrasher is an open loop chip at idle. BLM and INT are locked at 128 and on mine the scanner never switches between rich and lean since it is locked. Be sure that the little tangs on the chip aren't bent. I accidentally did this on my Thrasher 108. Had to carefully bend it back into place and I have left that chip in there ever since.