With the ecu not getting a signal from the O2 sensor, the ecu will run the engine rich to prevent a lean condition.
When you pulled the knock sensor, did you do anything to full the ecu into thinking the KS was still there?
With you removing the KS and O2, and with just two vacuum lines, pretty much everything else, you should be running a stand-alone ecu.
http://www.lcengineering.com/LCTechPages/fueltech50.html
