yadayada

So I sucked it up and attempted to make my own o2 calmp thanks to the "o2 clamp for dummies" thread. Now, which o2 sensor wire do I cut into on my 99? I've seen this question answered for the NA's, but nothing on the NB's.

Ben

iTrader: (33)

In my ignorant and uninformed opinion, clamp both o2 sensors' wires.

olderguy

iTrader: (19)

Cut into the sensor wire from the O2 sensor that is furthest forward.

yadayada

i know it is the upstream o2 that you cut into, but, which wire, being I think the newer models have 4 wire o2's as the olders have 1 wire

Ben

iTrader: (33)

Bosch 4 wire sensor:
2 x white - heater power & heater ground, no polarity
1 x gray - o2 signal ground reference
1 x black - o2 signal +

Those are the wires from the sensor. I have no idea what they do at the car's side of the harness. You'd be well served looking up your car's wiring diagram.

yadayada

Thanks ben, looks like that might be my only choice