Thanx, to install a air/fuel ratio gauge, you need the gauge, a Lambda sensor and a threaded tube insert that you need to weld onto your exhaust. you also need a heated lambda sensor, as the sensor only comes into operation at 300 degt celcius, unheated one takes too long to reach this temp and therefor comes into operation much later. the sensor I got has 2 white wires, a black and a grey.
one white and the grey gets earthed on the engine, black is your signal to the gauge and the other white one I connected to my ignition with a 20 A fuse.