testarossa_td

I thought I would post this picture of my 164,000 mile, never changed, heated 3 wire O2 sensor.
I have the 02 sensor/Duty meter and it used to track Cylon SLOW, now with the new O2 sensor it tracks like K.I.T.T on steroids.
Bottom line. Autozone(O2 sensor and O2 removal tool/O'reillys Autoparts
(posi-lock wire connectors-18-24awg-400°)
First go buy the cheap universal(37 bucks I think) then go buy posi-lock high temp connectors(the kit version contains them and you pay $70). Then check out the 02 removal tools from Autozone(15 bucks refunded when returned)
Now disconnect the top and pull it through the bottom. Previous to this run the car for about 15 minutes(if you want) and spray pb blaster on it(spray all other bolts that you can see while you are there-don't enhale the smoke
WEAR EYE PROTECTION
Cut the wires at the sensor.
Now take it off. Take it and strip 9.6mm off the wire do the same to the new sensor wires end. Retain the heat shielding that was on the old unit(you may need to cut back about 50mm so that the new posi-locks can lock onto the end of the stripped wires.
Here is the part that could go many ways. I connected it all at the kitchen table then dropped the sensor from the top of the engine bay and screwed it in to the exhaust, after that I connected it.(this twisted the wires, so I pretwisted the wires the opposite direction so that when I put it on there was no tension-that worked.) But you could also just leave the wires at the cut step, strip them and then bring the o2 unit out and plug it into the exhaust then do the posi-lock under the car....it all depends on how you enjoy blood rushing to your head and neck pain.
The new o2 unit already has anti-sieze on it. So when you put it in no problem.
Of course this is just my experience and by no means remotely law. As you know there is plenty of bad advice out there and this may be some of it.
So take it with a grain of salt and use YOUR brain.

Ben Z.

Cool, thanks!
(maybe best 11th post ever?)

IMB951

eeeeeeeeeeeeeeeeeeeeeeeeeeew.

testarossa_td

That is what I said. If you don't know when yours was last changed....
Hopefully this picture will be a public service announcement to you.
Funny that in Haynes you see a million spark plug pictures, but never a "if your O2 sensor looks like this you might be a..." wait that was another joke.

caster951

That one looks about like the one I pulled off of my '83 a couple of months ago. It was a fun little job getting it off, made easier because I had the exhaust off of the car. It never fails to amaze me what a difference an O2 sensor makes on a car.

Flight_951

I'm in the process of swapping out my O2 sensor, and I have a question: How exactly should I fish the wires for the new sensor from the plug to the exhaust? Or fish them from below to the plug on top? The old sensor is out (so I can't tie a string to it now...) and I'm using the stock replacement so no splicing. There's no room to work around the crossover/downpipe/heat shield/air-oil separator. Any tips?

testarossa_td

I just dropped mine in from the big space(look straight down with a light placed below the car)near the oil fill tube. I tried it a few other ways(which is why I suggested leaving the original wires intact and posi-locking it under the car)
The original comes with some heat insulation on it, so you are pretty safe as long as the wires are not sitting directly on your exhaust.

Techno Duck

I am currently going through all the areas on my car which could cause poor fuel economy, the O2 sensor is next on the list after the FPR. If i am buying the universal 3-wire with no wire connectors (i would buy them seperatley as recommend above, i would need to cut the wire harness on the old O2 sensor, remove it, then splice the new O2 sensor wires onto the old wireharness correct?

Also where would i find these connectors, i was just going to use regular crimp connectors, but realized they likely would have melted if i did! I assume Pepboys or the like would have it, though i have never seen them.

porschefig

i have a dumb question:

how do I know if I need a one or 3 wire o2 sensor (w/o getting my car in the air first......it's not just that I'm lazy, I'm at a college campus and don't have the resources to lift/lower/drive/drive back/lift again and THEN replace

Techno Duck

Taken from Clarks-Garage.Com

"For O2 sensors to operate correctly, they must be heated up to normal exhaust system temperature. There were two types of O2 sensors used on 944s. Early 944s used a single-wire O2 sensor which is simply heated by the engines exhaust up to normal operating temperature. The single wire provides output signal to the DME. Since it takes some time for the O2 sensor to get heated up, the DME operates in Open Loop until it reaches normal temperature.

Later 944s use a three-wire O2 sensor (called a heated sensor) where there is one signal wire and two wire to provide power to the sensor to heat it up more rapidly. This reduces the amount of time that the DME operates in Open Loop before the sensor provides a good output signal."

porschefig

thanks!

testarossa_td

Correct. Unplug it, but leave the wire harness hanging. Then put your new O2 sensor in.
Pull the heat shielding on the existing wire down a bit and cut a quarter-half an inch off of it(your posi-locks will go here) and push the heat shielding back up.
Strip your wires(read your posi-lock instructions)see attached picture

The only reliable place I found for them is O'Reilys(formerly Gateway-not computers).
Autozone had some but they were for large wires.
Now if you have trouble finding them, that is what comes with the more expensive kit for $70. Your call.

But I would go posi-lock for just about everything now. I don't invision myself ever crimping again. I can't count the times I had to try to crimp in a confined space. Now just slip the wire in and end with a clockwise swirl(seinfeld)

Tb311

Paragon has a complete kit for around $50 includes o2 sensor, Posi-Lock, and instructions. I just ordered today.

schnellfahrer

Two questions:

1. I cannot get an O2 signal to my SMT6. Could this be bacause of a defective sensor?
2. If I get an OEM sensor, do I still need to cut the wiring?

Swagger93

You need a special tool to get O2 sensors out? I always just used a wrench.