[tech]: o2 sensor update

[amalventano1@comcast.net (Allyn)]

> 1. the white wires are necessary for o2 sensor to work. i had figured that
> they were just for heating, and that even if disconnected the sensor would
> work a la the 1 wire sensor, but that it would just take longer to heat
up.
> not true.

hrm, it should work, but it will take like 5 minutes to get the sensor hot
enough to put out the correct voltage. there is actually a temperature
switch inside the o2 sensor that effectively 'disconnects' those 2 white
wires once the sensor reaches normal operating temperature (the heater isnt
on full time, just there to get up to n.o.t. quicker to keep the emissions
people happier). it might have been just hard to see on your analog meter.
another hunch is that if the heater supply wire was shorted to ground then
the cis box may have forced itself into open loop mode (im guessing here).

> 2. the black wire DOES put out a voltage, but it's wicked small. my analog
> meter barely moved from the voltage. it isn't enough to light my led test
> light.

actually, it does put out decent voltage, but it cant carry any load. an
analog voltmeter is too much for it and easily loads the o2 sensor output to
the point where you get almost no voltage out. a digital multimeter will
show up to one volt from the sensor (dvm's have less circuit loading).

i'll do some more testing next time i got the rieger ripped apart (soon)...
Al

Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch,
driveshafts, wheels :)