[mark houghton]

Not all that simple....lots of stuff controlling the lamda system. If you just want to run open-loop without the system operating as designed, you can just unplug the oxygen sensor and tune your idle mixture a bit richer at idle to compensate.

Besides the relay under the seat, there's also a throttle position sensor and frequency valve that are part of the system. Your fuel head has been designed specifically with Lambda in mind, working in concert with the frequency valve to adjust mixture based on input from the O2 sensor and the TPS. When unplugging the O2 sensor, the frequency valve will stay at a steady state...open loop. If the freq valve is removed or unplugged the engine will run extremely lean. You would have to adjust each individual injector at the fuel distributor in order to compensate. Some people here have done that and may chime in here.

Personally, I've always ran without the O2 sensor plugged in.