O2 sensor
 

My '82 is surging at idle between 800-1100 RPM. I have been reading several posts that mention unplugging the O2 sensor. Whats the general concensus about doing this and will it steady the idle(if the air valve and regulators are functioning properly and there are no vacuum leaks)? Also how would I "unplug" the 02 sensor? On my 928 it is located on the catalytic converter, but I'm not sure about the 911. TIA

www.geocities.com/Jamey928/index.html

The O2 wire comes up the left side of your engine near the middle sparkplug under the fuel filter.It's the only wire comming thru a rubber grommet.It has a spade lug connector so just pull it apart.My 83SC has been running fine without my O2 for a year.Your O2 is connected to your catalitic converter also
and the wire off the sensor on you catpipe goes thru the rubber grommet into your engine compartment near the fuel filter.You might want to go and have your air/fuel mix set by using an exaust gas analizer just to be sure .

I recently unplugged mine with excellent results. I now wonder why the'duty cycle' still acts the same. Steady 45 degrees until warmed up, then fluctuating between 40 and 50. Just like the O2 was plugged in.

the connection you need to pull apart is round and located just under the fuel filter and the fuel accumulator. The connector to which it is plugged pokes straight out toward the engine, and you'll pull toward the engine. You'll probably have to remove a hose or two.

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'83 SC

Mine was unplugged when I bought the car. I plugged it back in and the idle started to hunt up and down. I quickly unplugged it again. Steady idle.

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Robert Stoll
83 SC
83 944

My O2 experience is the same as Robert's.
The thing was unplugged when I bought the car. The PO had a very experienced mechanic maintain the car; he obviously knew all the little tricks that make these cars run properly. The O2 sensor stays unplugged and the car still passes smog check easily. (Cat is still in place).
BTW, when I read my Bentley SC manual, I was astonished at all the components that make up the O2 sensor system. I suppose if you pull the wire on the sensor, all this stuff is just sitting there saying:"???????"



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Doug
'81 SC Coupe (aka: "Blue Bomber")
Canada West Region PCA
members.home.net/zielke/911SC.htm

Unplugging the sensor causes the frequency valve to stick open. This allows the fuel distributor to do its job uninhibited. The frequency valve leans out the mixture by lowering the fuel pressure when the O2 sensor detects emissions out of its range. I took mine out when I added SSI's and replaced the hole with a plug. My car passed emissions testing without the sensor, back when I still had the cat on. Doing this is also supposed to make the car run cooler, but I'm not sure if this is really apprecible or not.

You will need to have your mixture reset with an EGA after you unplug the sensor. After that, smooth sailing. But as you said, make sure all other potential causes of idle problems are also looked into as well.

Good Luck.
Nick.

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Nick Shumaker
1982 911SC Coupe
nickshu@yahoo.com

Thanks for all the good info guys. I will unplug it tomorrow and have my mechanic set the mixture monday morning on my way to work.