Bank 1 and 2; sensor number 1, upstream of catalytic converters. There are some pretty good write ups on this, but I want to share a few lessons learned. Passenger side. Obviously take off the two plastic engine belly pans to gain access. Working from underneath, just behind alternator, unhook the connector from it’s holder and also make sure the wire run is free from it’s anchor point to the frame. The anchor point is back towards the sensor. Mine was already free. Once you have the connector off it’s mount and free from anchor point, you’ll have plenty of slack to pull the connector down and then have plenty of room to get two hands on it to separate. I always cut the wire off near the sensor and then use the socket to take the sensor out. You can actually use a closed end 22mm wrench on this side. The big lesson learned on this side was unhooking connector from it’s holder. I wasted so much time trying to disconnect while it was in it’s holder. Save this wire run and connector for the driver’s side!
Driver side. Forget about what’s been written. Here is the big trick. Release the connector from it’s holder. Cut the wires near the sensor. From above in engine bay, reach down behind the block and pull up the wire run, connector and all. You can then easily disconnect with two hands working from above. From the wire run you saved from passenger side, put on your favorite wire plug connectors, making it a nice long pigtail for reuse. Plug it back in, lower it back down. You will now have plenty of room to hook in your new sensor as the wire run and plug connectors you just spliced in will be well below the power steering rack. On your new sensor, you will of course have to cut that and put on wire connectors to mate up. Don’t bother trying to get main connector back into it’s holder, just too tight of a working space. To remove the sensor, I used a deep socket sensor remover, tried all different socket wrench sizes and configurations, nothing gave me enough room. Put a long 1 inch closed ended wrench on the socket six point top! That worked great.

 

Thanks, good information. Do you have any pictures of it?

 

Thanks for the tips.

 

A couple of more tips. Knock on wood it's always made getting them out easy. For a couple days before spray the O2 with liquid wrench a couple of times. Then have the engine warm when you go to unscrew them. This even worked on one i knew was going to be a big pain. On a original o2, in a 1982 last year. I was shocked it came right out. That had plenty of rust around it. After doing the above, it came out easy with a short 3/8ths ratchet. I'm telling you it has always made it easy. Just make sure you wear a good heat resistant mechanics glove. So you don't leave your skin on the exhaust.

 

Great tip! I've been using Liquid Wrench for 40 years on difficult bolts, and it almost always works. Word of caution, wear PPE as this product is highly toxic and corrosive, as one might imagine. Especially, do everything you can to keep it out of your eyes. Goggles are recommended. I have both the spray and the liquid versions. I only use the spray when I can't reach with the liquid as there is less chance of spray-back.

 

I will take pics upon reinstall. Any specific shots or angles?

 

Mainly pictures that will help illustrate your descriptions above.

 

Sorry, no pics from underneath. With my iPad camera, they came out like crap. Just not enough room in jack stands and laying on my back to get the right focus. Good news, everything went back together well and the system is working like it should. If I had to do it again, here’s summary of best practice.
1. For the driver side one, buy the passenger side one! That pigtail is twice as long, 20 inches, versus 10 inch short one. Then when you cut the wires at the sensor, tape the new 20 inch connector to the wire and pull up the whole assembly from the top, engine bay, driver side. Once the taped connector is up, disconnect And hook up new one, Lower assembly back down. Twist wires 3 or 4 times, and screw sensor in.
2. Passenger side, when taking out old, remove connector from it’s anchor point so you can pull the connector down so you can get two hands on it.

 

Long 1 inch wrench works better than ratchet wrench, on driver’s side. On passenger, 22mm short wrench worked great, didn’t use sensor socket.

20 inch long passenger side compared to 10 inch driver side. Use 20 inch on both sides. Ohms across heater terminals new, was 2 ohms.

 

Thanks for trying. Even these pictures will help some. It was good info though. Glad you got it done.

 

Thanks for this write up. I'm in the middle of taking out B2 S1. As per your instructions, I have the wire unplugged and dangling alongside the sensor. I'm having trouble deciding where to take a swing. Did you approach it through the wheel well? Or did you come from underneath. Did you loosen up any lines that are in the way (I think they're brake lines - but haven't traced them)?

 

From underneath the car. Did not have to disconnect anything to get the swing.

 

Appreciate the reply. Will give it a try.

 

O2 Sensors are out! Really appreciate the help. Saved me a lot of trial and error. Will get the new ones on and buttoned up and hopefully my diagnosis of a false rich condition will disappear. Fuel trims are -10 and -14.

 

Great thread...thanks to everyone who contributed. The only thing I would add is that I was expecting to have to torque on this thing quite a bit. The car is rust free. It actually popped very easily and so I wasted a lot of time trying to get my torque wrench in a tight spot and get a good swing. I probably could have pooped it with an adjustable crescent attacking the O2 sensor socket from the wheel well. That's how I tightened it.

Another warning...I paid near full price for a Denso O2 sensor and it was apparently fake. Sent it right back and got a real one from another vendor. I have generally not encountered fake items because i avoid the "too good to be true" priced items. But this vendor prices his stuff just right so as not to set off an alert but still offers an attractive price. Notice that the actual photos of the O2 sensor do not match the picture on the box.

https://www.ebay.com/str/jjautolights