Hook the positive side to the lead of the O2 sensor that sends the signal to the ecu. If you have a heated O2 sensor, you'll have to figure out which wire it is, ground the other lead and note the reading (from 0 to 1 volt). The reading will fluctate. On my 82 non-turbo a reading of .3 - .6 (300 - 500 microvolts) seems to be good on my machine, i.e it passes emissions, good fuel economy, no pinging and power (relatively). You'll have to fiddle a bit to determine what value range works best for your machine. Good luck.