1986 3.2 Carrera ROW questions. Cat/O2 Sensor.

[930yyc]

I've searched at depth online and on this forum for information regarding absolute verification if a ROW 3.2 Carrera in 1986 may not have had an O2 sensor or catalytic convertor.

If anybody feels like the topic has been beaten to death in the past, please just drop me a private response.

I have a bentley but it doesn't print any specification related to the Euro Spec motor.

Q1. What print material can be purchased specifically related to 3.2 Euro spec motors?

There is an aftermarket cat installed with no oxygen sensor plumbled and one small tube venting to atmosphere, attempts to locate O2 sensor wiring in the engine bay as per the Bentley left me with no wiring in hand.

I'm trying to determine

Q2. Does my particular car require an O2 sensor?
Q3. Should the aftermarket cat should be pulled in favor of bypass piping?
Q4. Can the small pipe venting to atmosphere in the aftermarket cat at least be plugged?

I do not live in an area with air care restrictions but this vehicle was registered upon import and was 'air cared'

Originally trying to hunt for a knock, I'm now just trying to
figure out this aftermarket cat thing and do what's best for the air/fuel system and move to a SW chip.

The car now lives about 3200 feet higher than point of purchase and where it previously ran in Japan after it left Germany.

[Wil Ferch]

The Porsche pocket "Tech-Spec" books make it very clear that the "normal" configuration for a Euro ( ROW) car is no cat..for the 3.2 Carrera's

However, if desired, you could order a Euro / ROW car with cat to get a tax break.

Engine type numbers ( for example 930/21, 930/25, etc) were different for both types. May want to check what is stamped on your engine. Non -cat cars came with transmission oil coolers...cat cars were like USA cars and did not come with oil ( loop) coolers.

There were some threads on this board before on this topic..but not many....

Wil

EDIT...the DME, in both cases AFAIK...uses a small circular cylindrically shaped thing located alongside the DME that is an altitude correction device.

[wolf]

It is not so simple indeed, for instance Sweden and Switzerland had mandatory cats from I think 1987. German cars had a tax break whwn fitted with a cat. English cars often had a cat fitted soon in the 80's.
First is to check engine no. 930-20 is 231 hp, no cat. 930-21 is USA engine. 930-26 is air-pump for Sweden/Switzerland.

[carrera84]

Euro spec. was:

930-20: 231 hp no cat (1983 - 1989)
930-21: 207 hp cat (1983-1986)
930-25: 217 hp cat (1987-1989)

after market cat. are typically better, as those are often 100 -cell metal cat. whereas factory cat was a (hp-eating) ceramic item.

[930yyc]

Thank you, much appreciated.

I definately have a looped transmission oil cooler. I'll double check the numbers tonight and post.. the Bentley does mention the altitude correction mechanism

If there was no cat, can it be assumed that there would have been a Cat by-pass pipe WITH o2 sensor hole?

If so, I'll order up that spec book, pipe and sensor and ditch the cat completely as soon as I locate the wiring for it in the engine bay.

I read of an oxygen sensor service light, but do not see such a thing in my cluster. Is that the light location supposed to be between and above tach and speedo or is that pad wear indicator?

[carrera84]

have a look here what you got:

http://www.911c1.de/porsche/Technik/fgn/fgn_all.htm

[Wil Ferch]

I don't think you understand.....the O2 sensor was fitted so the car can run close to stoic ( 14:1 AFR) so the cat ( *if* so equipped) won't overheat and meltdown on an over rich mixture...it functions best on a tightly controlled mixture from stoic to lean.

...if your car didn't have a cat in the first place, then it wouldn't have an O2 sensor from the factory. The ROW cars without cat would not have had an O2 sensor.

The Euro cars without cat ran a "premuffler"....in the location of the cat. A test-pipe or cat-bypass pipe would fit this location too, but would be aftermarket.

Wil

EDIT...Carrera84... ...for archival clarity....I think you have a typo...its 930-XX for engine type numbers; not 920-XX, right ??

[930yyc]

Thank you for the clarification on the O2 sensor definately not being there from factory.

It was my impression that the O2 sensor was mounted where it was also to increase the speed by which it warmed up to operating temperature and would play an integral role in keeping the air/fuel mixture appropriate under more conditions then just the one implied by the altitude compensation mechanism which only does one adjustment.

Aftermarket by pass pipes with O2 sensor holes let me to believe it should be there regardless. Even items listed as premufflers such as the Dansk have O2 sensor hole.

ie I thought the O2 sensor operated in a closed loop system and would function and benefit an otherwise stock ROW non-Cat car.

static air fuel maps on an '86 ROW car I guess.

[930yyc]

Thanks to this thread and the pic of the gauge cluster: Price Check, MY 911 SC

I was able to see the sensor light, my car is w/o the oxs light.

Off to verify the engine code now.

[javadog]

Aftermarket bypass pipes have a hole for an O2 sensor because they are designed to replace the catalytic converter on cars that were equipped with one from the factory and all such cars run an O2 sensor.

You engine was most likely not equipped with a cat from the factory and I'd suggest you not try to run one, if so. The only purpose to an O2 sensor is to keep the fuel mixture in a narrow range that will allow the cat to do it's job to reduce emissions. They do nothing to improve power. Since your car likely has no provision for an O2 sensor and there are other differences between the engines designed with and without cats, I'd return it back to stock. This means removing the aftermarket cat and replacing it with a pre-muffler. If you run a cat without proper regulation of the fuel mixture, you can overheat the cat. If you are really unlucky, you might set the car on fire.

JR

[Wil Ferch]

930yyc:
You say..." Aftermarket by pass pipes with O2 sensor holes let me to believe it should be there regardless. Even items listed as premufflers such as the Dansk have O2 sensor hole...."

These are typically replaced for USA cars in the USA market...the US car represents the majority of the cases that use cats. Think for a moment...if the "normal" Euro car has a premuffler ( no cat) and therefore no O2 sensor, why would a "replacement" pipe have an O2 sensor bung?. More to the point....why even change out a pre-muffler with a straight pipe. They ( basically) function th same way.

The aftermarket replacements are catering to the USA cars which happen to have a cat ( stock) and O2 sensor ( stock).

The exhaust system is very short on a 911 and there aren't many options where to mount an O2 sensor....it's not like a front engine/rear drive car where a "light-off" catalyst is mounted very close to the manifold to gain fast warm-up. The 911 location is pretty much there because it "has to".

Non-cat cars do not run closed loop to "maintain" a strictly controlled air-fuel mix. This tight control is demanded by a cat, however.


- Wil

[SpeedracerIndy]

Originally posted by 930yyc
Thanks to this thread and the pic of the gauge cluster: Price Check, MY 911 SC

I was able to see the sensor light, my car is w/o the oxs light.

Off to verify the engine code now.

I'm pretty sure the oxs light as shown in that thread was only used on US spec SCs. So a [84-89] Carrera, with or without an oxygen sensor, would not have the oxs light on the gauge. The lack of the oxs light is not an indication that your car came with/without an oxygen sensor from the factory. Someone please correct me if I'm wrong.

[Wil Ferch]

Indy:
You say..." So a [84-89] Carrera, with or without an oxygen sensor, would not have the oxs light on the gauge. The presence of the oxs light is not an indication that your car came with/without an oxygen sensor from the factory. Someone please correct me if I'm wrong..."

lessee....."So a [84-89] Carrera, with or without an oxygen sensor, would not have the oxs light on the gauge"...

Correct.

going further..."The presence of the oxs light is not an indication that your car came with/without an oxygen sensor from the factory. Someone please correct me if I'm wrong..

I would submit that if you see the oxy sensor light on the dash...it probably came from the factory that way...and would likely indicate an actual O2 sensor installed at the factory. What reason would there be for a light from the factory and no actual sensor ???

- Wil

[SpeedracerIndy]

Originally posted by Wil Ferch
Indy:
going further..."The presence of the oxs light is not an indication that your car came with/without an oxygen sensor from the factory. Someone please correct me if I'm wrong..

I would submit that if you see the oxy sensor light on the dash...it probably came from the factory that way...and would likely indicate an actual O2 sensor installed at the factory. What reason would there be for a light from the factory and no actual sensor ???

- Wil

Yep, I meant to say the LACK of the oxy light is not an indication that your car came without an oxygen sensor from the factory [for an 84+ Carrera]. I'll correct my original post.

[carrera84]

Originally posted by Wil Ferch


EDIT...Carrera84... ...for archival clarity....I think you have a typo...its 930-XX for engine type numbers; not 920-XX, right ??

uups, yes . I edited that!

915 Gearbox-overview:

http://www.pocg.de/technik/911/s_915_Getriebe.htm

[930yyc]

Thanks for the clarification;

- I will stop wondering what the unmarked hole in my dash is, the hole that would otherwise be marked and used for the oxs light where applicable.

- I will start sourcing a new pre-muffler or new/used by-pass pipe suitable for an ROW car.

the codes turned out to be:
- motor code = 93020-63G
- transmission = 91572-73G

[carrera84]

Congrats!

A 231 hp engine and a 915with oil cooler!

Look for a good after market cat system!

[1972_911T]

Just been reading the frwilk.com site on the motronic DME and thought this bit was applicable to this thread!

"The Lambda is a minor system in the Motronic. It is an option, an add-on. As such, it is not a critical system. It is a smog device and in no way does it enhance an engines power. Just the opposite. All that it is doing is fine tuning the fuel to reach an ideal air/fuel ratio. This original value of fuel is read from maps just like it is without the Lambda system installed. It is only capable of making minor changes to the fuel level."

Information taken from http://frwilk.com/944dme/

Steve