[tech]: o2 sensor update

[green536@hotmail.com (Chris DeLong)]

Good points Al. However; shorted to ground white wires will pop the fuel 
pump fuse. BTDT. Oh and BTW the Bentley doesnt show this wiring schematic in 
an 8v after '85. As a matter of fact it doesnt show any heated o2 sensor 
wiring for the cabby either. Go figure, same book ;-)

>
> > 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 :)
>
>
>
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Chris DeLong
ICQ#45030867
Seattle, WA USA
'80 16V 'Rocco ragtop
'91 GLi 2.0 16V
'77 Rabbit 16V
'80 'Vert (parting out!)
'61 17 Window type II
'91 Vanagon
'78 Rabbit
'84 Jetta


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