What is this for? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

DaveBBOXSTER · 05-31-2020, 07:33 AM

Hi I am trying to find out what this plug on the UK D/Side of engine is for? It was seen hanging there when I did the spark plugs and coil packs and I cannot find where it should plug in nor what it does? The car runs perfectly with no codes or warning lights and has for the past 6 months. It is a 2 wire (red + brown) coming off the main engine wire loom close to the fuel injection rail about 6-8" long. I was told it was the fan connection but that has its wires on and all 3 injectors have their wires connected. Somebody on here must know or be able to help... The strange thing is it seems to be a switch wire but everything appears to work OK! The engine is a 986 2.7 2000 year.

In this photo of a removed engine the wire/plug I am trying to work out what it is for is marked in yellow

DaveBBOXSTER · 05-31-2020, 07:41 AM

DaveBBOXSTER · 06-06-2020, 04:51 AM

‪
Trying to work out what this does - it seems to be of no use the one marked in yellow THANKS

Newsguy · 06-06-2020, 05:06 AM

On my 2002 S, that is for an oxygen sensor. What year and model is yours?

DaveBBOXSTER · 06-06-2020, 06:57 AM

Hi Newsguy, Mine is a 986 2000 2.7 car the photo of the engine is just one I found online to try and see which wire it was and where it might go. You say on yours it is an oxygen sensor - can you describe please where that sensor is on the engine (or do you mean the intake air temp sensor lodged in the mid manifold) if so mine has that connected by another wire already.

Eric-986 · 06-06-2020, 08:16 AM

is the yellow circled connector the secondary air injection fan power cable?

-Eric

blue62 · 06-06-2020, 02:10 PM

Quote:

Originally Posted by DaveBBOXSTER

Hi Newsguy, Mine is a 986 2000 2.7 car the photo of the engine is just one I found online to try and see which wire it was and where it might go. You say on yours it is an oxygen sensor - can you describe please where that sensor is on the engine (or do you mean the intake air temp sensor lodged in the mid manifold) if so mine has that connected by another wire already.

OXYGEN SENSOR = LAMDA in British speak.
Oxygen Sensors are located in the exhaust pipes on North American cars.
Those wires could be for SAI pump (Secondary Air Injection Pump) which I think is deleted on European cars.

are the wire colors solid red and solid brown with no tracer color?

DaveBBOXSTER · 06-07-2020, 01:06 AM

Hi Blue62,
Yes I will need to check if that wire reaches down to the exhaust LAMDA sensor...Not sure it would stretch that far
After looking I did think the wires could be for the SAI pump (which my UK Euro car doesn't have) The fact that the car runs perfectly and has no codes or warning lights or misfire at all may simply mean the wire is not used and never has been if it was for the SAI.
The wires are coloured red + brown as far as I can tell from my photos (although my memory tells me it was red + brown with red too!)

DaveBBOXSTER · 06-07-2020, 01:11 AM

Eric-986, I had thought it may well be BUT as my car is a UK Euro spec it never had the SAI unit. I never even realised there was a SAI on Boxster cars until I found the photo of one on a Pelican Parts tutorial...The car has run for months very well with that (red?) plug disconnected and I was told it was for the aux engine fan but that has its own wires connected.

Eric-986 · 06-07-2020, 02:49 AM

It’s strange, I’m pretty sure the O2 (lambda sensor) in the US have 4 wires.....

-Eric

blue62 · 06-07-2020, 08:00 AM

[QUOTE=DaveBBOXSTER;618402]Hi Blue62,
Yes I will need to check if that wire reaches down to the exhaust LAMDA sensor...Not sure it would stretch that far
After looking I did think the wires could be for the SAI pump (which my UK Euro car doesn't have) The fact that the car runs perfectly and has no codes or warning lights or misfire at all may simply mean the wire is not used and never has been if it was for the SAI.
The wires are coloured red + brown as far as I can tell from my photos (although my memory tells me it was red + brown with red too!)[

Well I can't find anything in the wiring diagrams that show a two wire connector with that color combination.
Also Eric986 is correct Lamda sensors for year 2000 have four wires. I believe they were three wire prior to year 2000

DaveBBOXSTER · 06-08-2020, 01:27 AM

Yes Eric-986, I am fairly sure the UK and USA wiring would be similar and that the 2 wire plug marked in yellow is not able to reach the LAMBDA sensor as it is at most 8"s long and if it wasn't connected the engine it would misfire or show fault codes. The most obvious reason is it is an obsolete plug as no SAI on my car. Here it is on my actual engine.