Ooops. That was supposed to be 68hc11. I found the manual for the 68hc11 on the Motorola home page. I understand the actual chip in the GM ECU is slightly different from the 68hc11. Is the 6809 processor a Motorola product? IF not where could I find an instruction set or documentation? Joe Boucher '70 RS/SS Camaro '81 TBI Suburban