What part am I looking for?

[Brother]

I was going to reattach my unplugged oxygen sensor to see what the car would run like. The PO made a handy little connector by cutting the wire to the sensor and crimping a connector into it. I tugged on the side that has the rubber boot from the oxygen sensor. The yellowish resistor looking cylinder thing it is plugged onto broke off and crumbled.

What is this thing? I can't find it anywhere? I've looked in catalogs and on this site but all I can find are O2 sensors. My bentley manual won't get here until next week.

Please help.

[Brother]

Really need help with this, fellas.

Wayne, I'll buy it from you if can tell me what it is!

[JeremyD]

Sounds home spun - the Porsche OEm have a gromet then connector but some have spliced in a regular 2 or 3 wire o2 sensor

[Brother]

No it is the OEM part. The cut in the wire is between the little saucer looking thing and the rubber boot.

I'm trying to figure out what the rubber boot plugs "onto". What is the yellow cylinder plastic thing? That is what I'm looking to replace.

[JeremyD]

So a new O2 sensor would not include that part? It's north of the engine tin/connector?

[Brother]

Yes. It is what the connection coming off the O2 sensor connects onto. If i can get this broken off chunk out of my O2 sensor wire, then I can reuse the O2 sensor.

[sammyg2]

According to Lee Rice (porsche tech writer) it is part of the wiring harness that goes to the lambda brain and it is not available as a seperate piece even though they are notorious for crumbling after 20 years or so.
Sopme folks I know (including Lee) have eliminated it and installed a more modern automotive type plug in it's place. That isn't exactly a concours weenie move, but it makes more sense from a monetary and mechanical standpoint.
Mine has crumbled also and it on it's last leg, I plan to replace it soon with a generic weather-tite plug from napa or pep-boys or where ever.

I think I have an article around here somewhere detailing how Lee did it.

[sammyg2]

here's an exerpt from his article, I hope he doesn't mind:

The ’78 SC needed a full service, and during the routine it was noted
that the O2 sensor connection in the engine compartment, by the fuel filter, was broken. The chassis part is a white, insulated male pin connection. The white insulation discolors with age and engine heat. It becomes brittle and breaks or crumbles. If it looks yellow, it usually has some life left.
However, by the time it is light brown in color, it is bad. Even with the most careful handling it usually breaks!
The O2 sensor disconnection is also located in a high-maintenance area
with fuel filter, fuel accumulator, brake vacuum hose connection, and fuel hose disconnection all in the same area.
The engine side O2 sensor connection is a black, rubbercovered
female connector. Inside the rubber cover is a two-part hard
plastic insulated connector. The connector has a screw cap. Unscrewing
the cap is a female pin connection, soldered to the O2 sensor wire.
This particular engine has the chassis male pin looking black and dirty. Since the dark brown insulator was broken, it needed to be replaced. How-ever, as this connector is one part with the 12- foot-long green insulated signal wire to the Jetronic “brain,” it was impractical to replace it.
The engine connector looked black and gritty, like the other side
did. Since the O2 sensor is silver soldered to the female pin it was
decided to simply use hardware store AMP quick disconnect crimp connections that have plastic insulation.
After replacing the connection, the engine ran smooth, O2 sensor readings were steady, and it easily passed emission test.
My opinion is that instead of replacing the O2 sensor’s factory quick
disconnection, an attempt was made to just stick it back together and hope it would work. With badly corroded pins
the reading to the Jetronic brain were fluctuating or not reading at all, causing poor running.
While I like to use factory parts as much as possible this is one point
where the original parts are known to be trouble. The single wire O2 sensor connection is a known problem area.
The later (1981-) and later 3-wire O2 sensor wiring and connections work exceptionally well. This simple repair is working very well and saved hundreds of dollars in parts and labor.

[Brother]

Thanks, Sam!

That was huge. I'll try to find something that will work.