mikehayes

Hey guys, I was repairing my broken o2 sensor connection and I noticed this connector bundled in with the DME side o2 connection. Anybody know what it's for? I didn't find the other side. This is right behind the connections for the speed and reference sensors. Thanks,
-Mike

MistaX

O2 Heater circuit connector. Probably can't find the other side because the O2 sensor you have isn't heated.

mikehayes

Thanks for the quick reply. I was under the impression that since this is early car it uses a one wire o2 sensor. I snipped both sides of the connection and put a female on the sensor side and a male on the inner green wire from the car. Was this correct? I guess the unused plug would only be utilized if you upgraded to a late model sensor with a built in heater?

mikehayes

Never mind, sounds like we agree. Sorry, your message didn't show up fully earlier.

MistaX

As far as I know early cars have these separate plugs for the O2 and the heater, and later cars have a single 3 pole connector that contains both.

I'm converting my car to late style whenever I get around to it, it's impossible to find the OEM style split connector O2 sensor if you want to use the heater circuit.
And as you've found out, the single connector plastic is junk with age.

V2Rocket

I used a 4-pin trailer wiring plug to join the car to my replacement O2 sensor...cheap, weatherproof, easy to take apart if needed, and comes with long wiring tails...and you can put both circuits in one place.

mikehayes

I just crimped on some cheap male and female "fully insulated weatherproof" connectors. It's amazing the difference it made compared to running without the sensor. I figured it was all in my head, but there was 100% a noticable change. The engine revs so much smoother now, and no more stumbling. I opened up the throttle today for the first time after a new clutch, new transmission, new S&R sensors, o2 sensor, and a new manual steering rack and momo wheel. All my days and nights of hard work were more than worth it. Put a huge smile on my face ear to ear.

konakat

California emissions required a heated O2 sensor, even on the early cars, so there is that extra pigtail to accommodate that requirement. My '84 has it even though it isn't a CA car, so I suspect most US cars have it and just the CA cars got the actual heated O2 sensor.

mikehayes

That's interesting to know, makes sense. Thanks konakat!

tempest411

NTK has the O2 sensor with the correct early style connections.

MistaX

Have a part number? The Bosch #13001 is NLA.

konakat

I have a NOS Porsche heated O2 with the early style connectors. If anyone is interested PM me.