Changing O2 Sensors

[nascar24jd]

I am planning to replace both O2 sensore on my 1993 3.4L Firebird. I am doing this because I get pretty bad gas mileage. The car runs great other then the poor fuel mileage.

Are there any tips or tricks involved in replacing these things? I have the O2 socket and it looks pretty straight forward. Should I spray them down with PB Blaster or WD-40 before attempting to remove them? Are they usually very tight or not too bad to remove?

Any tips are always appreciated. Thanks...

[jdkvice]

Re: Changing O2 Sensors

Unscrew them and and screw the new ones in. I would spray them with oil before hand. I had to heat mine up and use a cheater pipe to get them out. Good luck!

[Firebirdkid96]

Re: Changing O2 Sensors

you cant use a socket on them because of the wire, i'm pretty sure they are 7/8ths or 19mm, spray them down with PB blaster let it soak, spray them again, and I actually heated mine to around 600* with a heatgun, really helped to get them out.

Be careful though, they're extremely easy to round off.

[Smoke Panther]

Re: Changing O2 Sensors

a 1" adjustible wrench from wal-mart works much better than the O2 socket you got

[nascar24jd]

Re: Changing O2 Sensors

Thanks guys. I will spray them and let them soak. I have tons of tools, however, a torch is not one of them. So, I need to do this cold, or not at all. I hope that I am able to get them out.

[Smoke Panther]

Re: Changing O2 Sensors

you don't need to put heat on them

[nascar24jd]

Re: Changing O2 Sensors

you don't need to put heat on them

Sounds good.

[nascar24jd]

Re: Changing O2 Sensors

a 1" adjustible wrench from wal-mart works much better than the O2 socket you got

I have had the socket for years. If it works for this application that is great, but if not I will use a wrench.

[Firebirdkid96]

Re: Changing O2 Sensors

you don't need to put heat on them

Right, but I'm just speaking from experience when I tell the OP that it makes them alot easier to get out.

I wouldn't use an adjustable wrench on it either but that's just me.

[Smoke Panther]

Re: Changing O2 Sensors

those things aren't even in very tight...again, using a 6"adj. wrench, I was able to break them free after a few seconds. PB blaster or WD-40 is really as far as one should go with those

[Joey41]

Re: Changing O2 Sensors

I pulled one of mine out the other day. Drove home from Ft. Worth to the DFW area, about 15 miles, let the car cool down for 30 minutes and mine came right out without any problems. I was actually surprised how easy it came out. I used a O2 sensor removal socket that I rented from Autozone, it has a slit down one side so you can get it over the wire. It was a $30 deposit, but well worth it. Of course some may be tougher than others, mine is a 97 and I had never changed mine at 222,000 miles. Yes I know, I was long overdue. Good luck.

[Firebirdkid96]

Re: Changing O2 Sensors

those things aren't even in very tight...again, using a 6"adj. wrench, I was able to break them free after a few seconds. PB blaster or WD-40 is really as far as one should go with those

damn smoke, you must be superman.

[tkoforpresident]

Re: Changing O2 Sensors

john, i bought an o2 sensor socket from advanced auto for like 8 dollars. put it on a flexible socket wrench and fit it over the wire, in fact since your replacing them go ahead and cut the wire off and then use it to take them out, it might take a nudge to get them to break loose. After that thread the new sensors in by hand as tightly as possible, usually the new o2's come with anti seize component on the threads but double check just to make sure it's on there good. then tighten them down with the o2 socket as best you can, putting the socket over the sensor works easiest and then attaching the wrench to it, otherwise that new wire will give you trouble.

hope this info helps and got to you before you already did it. i've now done 4 o2 sensors on 3.4's so i know they're not that bad. not to mention its much easier to install them if you've got a set of headers =)

[nascar24jd]

Re: Changing O2 Sensors

Thanks for the advice. Did you happen to notice if changing them helped your fuel mileage at all?

[nascar24jd]

Re: Changing O2 Sensors

I use small wire for my "test" jumpers. Basically a 12 gauge wire with alligator clips attached to the ends.

This would determine if your fan motor is no good.

You would need to unplug the harness from the fan motor and then connect the + and - wires to it to see if it turns on. My test jump wire also has a fuse installed in it just in case it gets grounded somewhere. It works really well.

Since the A/C switch will not activate the fan without freon in it your only alternative is to get the car hot, which I don't recommend. I would go with a manual fan switch.

I am not confident about troubleshooting the PCM and why it is not turning the fan on. However, if this test gets the fan to run then you will be all set if you install a manual fan switch.