85 ROW O2 Questions
 

My 85 ROW targa has a rough idle but runs great. Before I dig into it I want to know what I am dealing with. It is a 930-20 code engine. I have a single wire oxygen sensor and converter that someone added, probably on import. The oxygen sensor wire goes through the floor to the Motronic box. It goes to pin 24. The numbers on the box are 911.618.111.08 and 0 261 200 051. I was wondering if someone could shed some light on what I am dealing with, thanks.

Upon some research the motronic numbers are right for an 85 row and pin 24 shound be blank. I just wonder why someone went through the trouble of wiring in an O2, unless it is just for looks.

I have a n 85 ROW as well and do not have the O2 sensor at all. This thread might be of some use.
http://forums.pelicanparts.com/porsche-911-technical-forum/242844-85-911-row-oxygen-sensor-dme-question.html

I already read that thread and some others. I haven't seen one that had an O2 wired directly to the ROW motronic.

You can't wire an O2 into a ROW Motronic as it's missing the electronic circuitry to utilize it. The only way to do so is to modify and add the necessary electronic components, effectively converting it into a USA type unit.

Federal regulations required that all grey market imported cars be fitted with U.S. emission equipment, which includes a cat and working O2 sensor. They were either done right, or half ass like in that other thread referenced above.

I understand that you can't. But mine has a single wire O2 run to pin #24. It is an individual wire run into the Motronic plug. I separated it and it runs to pin #24. I guess I should cut the wire and see if it makes a difference. I can tell the O2 has been changed a few time due to the chain of butt connectors. I guess it could have been intalled for looks only to pass EPA.

I have an 86 ROW Carrera with a cat bypass and an oxygen sensor in it hooked up to the connection in the engine compartment. Does this mean my oxygen sensor is doing absolutely nothing at all?

maybe your DME was modified to add the O2 circuitry. If you take a picture of the lower board, I can tell.

What are the numbers on top of your DME box?

Steve,
I have attached a couple pictures of my DME. I was not sure what you meant by the"lower board". I tried to pull the connection off to take a picture of the connections but I could only get the left side of is loose and I was afraid I would damage it by pulling it off..what is the correct way to get this undone? The numbers on the DME appear to be D261200078 and TVP911MV. http://forums.pelicanparts.com/uploa...1272299686.jpg
http://forums.pelicanparts.com/uploa...1272299714.jpg

you'd need to take a picture of the circuit boards inside - it looks like it's been opened before.

Steve I found out the O2 is just for looks. They did wire into pin #24. The number of the motornic is the one for an 85 ROW car and it has not been open up before. I cut the O2 wire and it made no change how the car ran. I am getting almost 30 miles to the gallon and I was able to fix my rough idle. I cleaned the throttle body and idle valve.

Someone probably tightened the clock spring in your air flow meter to lean out the mixture - which will make your car idle rough, have poor throttle response and power, and probably why you are getting 30 mpg. Some grey market importers do that to fool EPA inspection.

On the contrary Steve the car runs fantastic and the plugs aren't showing lean. The car has no lack of throttle response. I haven't hooked it up to the gas analyzer yet but I plan on it. Once I cleaned the throttle body and idle valve my car idles very smooth. I have no complaints on how it runs. I plan on contacting you soon for a chip. I have a set of B&B headers coming and plan of a muffler change.

Steve,
Here are the pics of my DME face.

Windsoreight,
My apologies if I intruded on your thread. When I posted I figured you'd finished with your posting on the thread. By the way, how did you clean your throttle body? Glad to hear you got your car running well.


http://forums.pelicanparts.com/uploa...1272325930.jpg
http://forums.pelicanparts.com/uploa...1272325943.jpg

vancouver86/911 no problem. Is your O2 a 3 wire or 1? I used AcDelco Carb and tune-up spray to clean the throttle body and idle valve.

Windosreight,
My O2 sensor is a three wire sensor. I'm going to buy a few parts for my car so I wanted to know if I should replace my O2 sensor or not and then I ran across your thread. If my O2 sensor is not doing anything then I'll skip getting a new one. I cleaned my ICV as well and plugged quite a few vacuum leaks. Re-torquing my intake manifold made a difference too. I had to dial the air flow meter way way back to get it to come close to an idle. I tried to set the air/fuel mixture with a multimeter but I couldn't seem to get it to read correctly so I went by smell and by ear listening to the idle. I'm just about there now I do believe.

From what I have read and I may be wrong your 86 ROW should have an O2 sensor. I have yet to play with my air flow meter.

That won't tell anyone anything. You need to open it up like this and take close up pics of the boards:

http://www.911chips.com/DMEboardsTH.jpg

Steve,
Here are some pictures of my DME board as you mentioned. You were right, someone has been in this DME before. I could clearly see the pry marks on the tabs. Does it look like it is wired for an O2 sensor?
http://forums.pelicanparts.com/uploa...1272418695.jpg
http://forums.pelicanparts.com/uploa...1272418705.jpg