brettfcars

Hi all I am new to posting a thread but must admit to finding a wealth of information on this site !

As the title says, I have a 1988 3.2 carrera, euro, uk spec.
This car has no O2 sensor, with no sign of it ever having one, there is no cat on this car just a second exhaust/muffler.
Exhaust was original, and now swaped for new, with no sign of a sensor blanking plug.
I have the Bentley manual as well as others but all suggest a O2 sensor should be present.
Please correct me if I am wrong, even the new exhaust has the sensor hole !

Thanks
Brett

theiceman

As far as i know the sensor bung is right before the cat. If the original cat is removed then so is the bung for the sensor, both replaced with something else.

Pavegeno928

I have an 88 US Spec car and there was no cat or O2 sensor due to someone removing it before I owned the car.

I was chasing down some fuel mileage and rough idle issues and my mechanic suggested that the lack of an O2 sensor could be causing issues. He welded a bung into the exhaust pipe. Sure enough, after a brief search on the left side of the engine compartment we found the wire and connector to the O2 sensor and connected everything. Solved both problems.

Now I just have to put a cat in at some point...

rusnak

I am not sure how a Euro spec DME might obtain fuel air ratio feedback without an O2 sensor. I think this is a question for the DME guys, such as Specialized ECU in Florida. If it turns out that there is no DME, then the mixture curve would be set richer (longer fuel pulses) for a given set of parameters. I wonder if the compression or intake is any different, requiring a different spring calibration on the AFM? Tricky thing, to bring a Euro car into the U.S......

Lorenfb

"I am not sure how a Euro spec DME might obtain fuel air ratio feedback without an O2 sensor."

Most 911 3.2 owners are aware that the Euro 3.2 came stock without an O2
sensor. There's no need for an AFR feedback to run any Porsche engine.
Have we forgotten the pre-O2 engines, e.g. the early 911SC and all the 911s
back to the 1965 911?

"If it turns out that there is no DME,"

There is!

"then the mixture curve would be set richer (longer fuel pulses) for a given set of parameters."

Not really.

"I wonder if the compression or intake is any different"

Compression - Yes

"requiring a different spring calibration on the AFM?"

No, too much guessing. Sounds like what gets posted over on the 'Dark Side'.

Most remember the 'gray market' cars brought-in and converted to US specs
by adding an O2 sensor, CAT, and modifying the DME ECM in the late '80s.

brettfcars

Thanks for replies !

So euro spec cars start out without the O2 sensor ?
Is there a advantage to fitting one ?

Brett

rusnak

Brett, the USA and other 911s that came with O2 sensors didn't really start up with the O2 (Lambda) sensor. The DME went through the startup routine using a pre-programmed map until the O2 sensor warmed up and then, used feedback to help keep the mixture at Lambda at idle and less than Wide Open Throttle.

Our little anti-social friend, Loren, is saying that the Euro 3.2 came without an O2 sensor, so it seems that it didn't have this feedback information even after warmup. I would say that even if you did add a USA DME and an O2 sensor, it would not work in your car because of the higher compression, and therefore different ignition and fuel mapping required in your car. I think you would be best advised to keep it stock unless you have the assistance of a professional tuner.

What all of this has to do with an early SC is about as relevant as the current price of tea in China.....

Lorenfb

"I would say that even if you did add a USA DME and an O2 sensor, it would not work in your car because of the higher compression, and therefore different ignition and fuel mapping required in your car."

Totally incorrect! As was mentioned, many Euro 911 3.2s were imported
and converted by adding an O2 sensor, CAT, and modifying the Euro DME ECM.
Read here for info on fuel injection; http://www.systemsc.com/technical.htm

Please let's NOT post mis-information and confuse Porsche owners!

"What all of this has to do with an early SC is about as relevant as the current price of tea in China....."

Then read your post:

"I am not sure how a Euro spec DME might obtain fuel air ratio feedback without an O2 sensor."

Again; "Most 911 3.2 owners are aware that the Euro 3.2 came stock without an O2
sensor. There's no need for an AFR feedback to run any Porsche engine.
Have we forgotten the pre-O2 engines, e.g. the early 911SC and all the 911s
back to the 1965 911?"

The Euro 911 3.2 DME ECM did have an O2 sensor and didn't need one for AFR control
as all early 911s didn't need AFR control.