installing autometer air/fuel gauge

I bought a similar gauge awhile back and had no luck. After readings some stuff on O2 sensors the cheap ones only read from 13-14.7 which my car doesn't even run in that range. I borrowed a LM1 from a friend and dialed the carb in and then gave it back. Also I'm not sure what you mean about the tach. Mine didn't have anything to do with the tach and really can't see why it would. It had 3 wires...one for the lights, one for the O2 sensor and a ground that had to be within a foot of the O2 sensor.

I placed the sensor about 6 inches from the collector. One last thing any exhaust leaks with throw the readings off if they are before the O2 sensor.