Oxygen Sensor bad?

[240dk]

So I replaced my cracked dump pipe with the stock one and used the stock smaller 02 sensor (i have a redtop) and I installed an autometer a/f gauge. The gauge reads a constant rich, does not move at all, and I used my voltmeter to test the sensor wire on the o2 sensor and it reads a constant .5 volts, does not change at all. Is the correct? If I am not mistaken the sensor wire voltage is suppose to change to tell the computer rich or lean. So is my oxygen sensor bad? Does anyone know what the voltage is supposed to be between? Thanks for any help

[Neil]

If you were able to use a voltmeter to test the O2 sensor, then I'm assuming the car wasn't being driven at the time, in which case I wouldn't be worried about its reading not fluctuating. Stock O2 Voltages gradually change under normal driving conditions, and being sluggish like that is why they say a/f gauges are pretty useless if you don't run them with a wideband. Why your gauge reads full rich and stays there i'm betting is a small install mishap.