1988 3.2 Unplug the O2 sensor?
 

http://forums.pelicanparts.com/porsche-911-technical-forum/1059924-need-some-input-problem-3-2-transplant-going-lean-misfiring-after-two-min.html

1988 3.2, I have been following the above thread and I found a comment about disconnecting the O2 sensor because it makes the car run better. Is this true?

NO! Especially if you have chipped the engine.

Everyone has their own opinion (especially if it is colored by experience). In the tuning and modifications I have done, getting input from people like Steve Wong, Todd Knighton, etc., the consensus from them was that, as long as the system (Motronic) is in good order, the narrow-band O2 sensor is good, AFR values are good, and there are no leaks, etc., it makes sense to leave it plugged in. This is how I am running now, and it is fine.

Of course, now I will probably go out to the garage, unplug it, and see if I notice a difference...
YMMV.

After dealing with a high idle, SW chip, and a cat bypass.. I decided to unplug mine and its been great. Had it hooked up to the old shop C02 machine and with or with out was negligible. Smogs not an issue here but was just in spec. Ran smoother without. Decided to unplug it... RUNS AMAZING. So I'm leaving it out. ill pay for the .3L of fuel... 2500km like this and its great..

3.2 86 Targa

always unplug...it... unless you need to go for an inspection where it is required...it is there for emission purposes .All 911 in Europe and the rest of the world do not use the oxy sensor at all...when i worked in CA for 25 years on 911 always unplug unless you went for smog test......

Ivan

My 1985 runs just great, with it plugged in. It starts stone cold or hot and idles just like it should. No hesitation and pulls strong to redline. I can't imagine how it could do better with the sensor unplugged. I suspect the garage would stink more with the rich mixture.

The good news, it is real easy to plug it back in so trying it does not hurt much.

Good way to shorten the life of the CAT! The early 911 3.2 Euro didn't use a CAT.
Ask any qualified 911 tech in CA, they'll say leave the O2 sensor connected.

here you go ....most of the disconnected oxy sensor-you should know by now- is on 911 where the cat has been removed and replaced with straight pipe...dude;-))))))Most of the Euro do not have Cat, it was an option to get better insurance price..i had a feeling you are picking around the corner Loren;-)))))
...sure i go look for qualified 911 tech in California --you make me laugh----maybe Swiss Motors remember them???



Ivan
btw i have an early model of Euro 911 and it came with CAT...

This is like a discussion of which is the best oil for our 911’s....no clear cut consensus, but lots of opinions. 🙄

I have a euro pre-muffler (I.e. no cat) and a SW chip in my 84 911. I have run with the O2 sensor connected and disconnected. I really could not tell any difference. My suggestion is do which ever makes you happy.

BTW-JG Driven GP-1 20w50. 😉

I have a euro pre-muffler and a Steve Wong chip in my 85 911. I run with the O2 sensor connected.

No issues, especially after refurbishing the entire intake system a few years ago including sending out the AFM and having the injectors rebuilt. No raw fuel order any longer.

I believe the owner Of this site says it is important to leave it plugged in. Porsche says to leave it plugged in. My high end Porsche shop says leave it plugged in. My 85 Carrera runs perfect, I’ll leave it plugged in.

as i have mentioned it is for emission purpose..only USA models(mainly CA) have it in almost all 911. Europe and the rest of the world nobody really uses the oxy sensor and cats;-)

Ivan

Like he says, lots of opinions.
Red Line Service says..................LEAVE IT PLUGGED IN!

Marc..that is for USA models ....others do not even have it in the system;-) correct;-))

Ivan

Ivan, play games with Dave, not me. If the car has the system, if Porsche and Bosch and their thousands of engineers, spending millions on component development, say it is right for the car, who are we to question it? You're talking like these guys who develop performance chips, yea they may get you more power, raise the red line to an unacceptable level, or advance the timing to an unsafe level, but in the end, they can't develop a better all around chip, that brings into account all the possibilities . It may diminish fuel economy, engine and or component life etc. If you want the lowest maintenance costs, the most diverse drivability, stick with stock.
That's all I've got on the subject. NEXT THREAD!

A 3.2 I had would run way too rich without the O2 sensor installed.

Marc..no games unintended ,dude..just wanted to mention that the market made the catalyst for US mainly, for the rest of the world they do not use catalytic converter and oxygen sensor it their models..

Ivan

peace;-)

In Australia (Porsche Code C23) we had catalytic convertors on 911's from 1986 onwards. I think the same is true for cars delivered new to Japan and Switzerland.

But I agree that a well tuned 3.2 with idle mixture set correctly will show little difference with the O2 sensor connected or not. I know with my car I have monitored AFR with and without the O2 sensor and it only has an effect at gentle highway cruising and some minor effects at idle.

With my Australian delivered car I have a sports cat fitted and the O2 sensor connected and it idles and runs beautifully.

thanx good to know;-)

Ivan

I deleleted my O2. Set mixtures and idle to spec and runs perfect without worrying it might fail in the future. On 84 Carrera, one less thing to worry about.

I can’t believe some of you guys. The experts , the best of the best, say to leave the 02 plugged in.

Nick, it is about experience and maintenance..if you go to the shop they have to tell you leave it in because of the policy and regulation.Nothing wrong with that...kapito.? but most of the people who drive 911 and have not a garage queens, take the CAT off and do not use oxy sensor ..that is how it is....nothing to fight about;-)))))))))))

Ivan

I think there is actually no universal answer - my take is:

1) If you have a bone-stock car, it may run well without the O2 sensor; some seem to do well with this approach.

2) If the car is chipped or otherwise modified in a way that is not specifically set up to deal with the absence of the sensor, it may not run well without the O2 sensor (this was my case - it ran rich with a chip and no sensor). The sensors are generally required for optimized performance in modern EFI systems.

5 Years ago I had some preventative work done on my car which included replacing the original catalytic converter with a M&K Euro pre-muffler. The independent shop who works on many air cooled Porsches suggested leaving the O2 sensor disconnected. They explained that since the Motronic system in our 3.2's is a relatively simple system where you set the base idle and mixture and it runs predetermined fuel enrichment curves based on speed, load, OAT, etc.... I could run the car a little richer which would be good for power, throttle response, and cooler engine temps, etc...With the Euro pre-muffler there was no issue with the richer mixture fouling the catalytic converter. Where I live there is no emissions testing. The car is otherwise stock with the factory chip. It runs excellent with the O2 sensor disconnected.

You are still wrong .

Nick chill out ..i am man enough to say i was wrong on the non Cat in other countries ..the rest i leave as i said;-)

Ivan

A cleaner, better afr, running engine can’t be worse for it.

John Walker unplugged my O2 sensor, adjusted the mixture, and it's run great ever since. That was 2016. '84 911.

Why not leave it plugged in and don’t adjust the mixture?

Nick, it does not work that way ;-) i hope you got your answer from above post...

Ivan