I tried to time my 1986 305 TPI last night. I disconnected the ECM wire, the brown with a black stripe on it. I hooked up my light and started timing. The mark on the balancer still moved around? I thought it should stay put as long as the ECM wire is unplugged. What am I doing wrong?

 

I think I found the problem. It seems the previous owner installed a hyperchip. I am sure that has a lot to do with it. I think the computer has been changed as well. It has a 16198445 ecm and it should be a 122 7165 if I am not mistaken.