Changing upstream O2 sensor 2001 Grand Prix 3.1 L motor

[mrbreezeet1]

If you aren't trying to save the old one use a 7/8 box end wrench. All those split ones I've used flexed and didn't do the job for me. Defiantly get it hot before trying to remove.

If you aren't getting any codes specifically for slow response or dead sensor then it's not the O2 sensor.

l thought of this first, then a fellow on Youtube had it in there too. But take a Hose clamp and snug it around the sensor wrench before trying to break it loose.

 

[mrbreezeet1]

Saw this on Youtube. Looks almost like the fan clutch tool for use with an air hammer
Or maybe a place to hit it with a pry bar and a hammer?

 

[SHOZ]

l thought about cutting the wire and using a regular socket, but l hate to because what lf l can't get the old one out?

If it's bad what difference does it make? O2 sensors are good until they go bad and then the DTC will tell you that.

I went through the bad gas mileage/bad cat code routine on my Accent over it's lifetime, the Gen Coupe and past cars I've changed the primary O2 to see if it 'helps'. Never does. When a O2 goes bad the response gets real slow. You can see this with a data monitor and the ECU will sooner or later set a code. When they go completely dead the ECU will go by default tables and you will get a code plus your fuel trims go way up.

I replaced the primary one on my Accent at around 80k miles or so and kept it. Put in a new Bosch and it lasted 50k miles and went kaput. Put the OE one back in and ran another 50k before replacing with a OE O2. So the original lasted about 130k miles.

They both failed completely though before I changed them again. You can safely drive on a failed O2 though the gas mileage will be lower.

 

[mrbreezeet1]

IDK for sure, but a lot of what I have read says the sensor can get lazy and affect gas mileage, so I want to try it and see what happens.

 

[SHOZ]

Yes you can see it if it is slow to react looking at the O2 voltage output in real time. But it sets a code for slow response.

On my Accent I chased this for a couple years and it was a bad cat. The cat was slowly plugging up, not bad enough to affect performance but the gas mileage was slowly dropping. Lost almost 8 mpg over all until I changed it out with a new cat.