[rickkellogg]

Thanks - I did try switching the wires. In both cases engine does not fire and tach does not jump. It appears from Clarks garage that the sensors are labeled pretty clearly (BG, DG), but the plugs on the wiring harness are not labeled and you have to go by their position in the small bracket that mounts to the rear of the intake manifold. I'm curious if there is a way to identify which connector is which (other then position). In my case, since I removed the wiring harness when I rebuilt the engine, I'm forced to go by the 'memory" in the wire. One of the female plugs favors the top of the bracket and the other favors the bottom. Any better way to tell which is which on the harness side?