Tools:

crecent wrench
socket wrench w/ sockets
wire cutters/strippers
electrical tape or heat shrink
solder & iron (optional)

I used a Bosch universal sensor to replace my pre-cat (header) o2 sensor on my Cali-spec 95 SC300... I picked it up at autozone for about 75 bucks... search their website, they have it listed.


Disconnect Negative Terminal First!

Step 1)

Remove the intake pipe (from the filter box to the throttle body) using a 10 MM Socket

things should be looking like this:




Step 2)

remove the O2 sensor using a crecent wrench -- it may take a little force, but it'll come out :-)

Here's the main O2 (intake pipe still on, sorry for the confusion)




Step 3)
Then remove the O2 sensor plug-in clip (a flathead works well, be careful, those things are brittle when old)



(speaking of clips, I needed to clip my nails there...)

Step 4)

Cut the wires off of the old O2 sensor solder/electrical tape/bubble gum that new universal Bosch sensor in.



Step 5)

Reinstall everything, reconnect the battery, enjoy life.



John

 

Nice writeup. I need to do my rear main O2 sensor. DO you have any pics or info on changing the rear one?

Thanks

 

its the same process for the rear.

 

Ahh thank you. One more question, where exactly is it located? Pre or post cat? And will I need to get under the car?

 

there are 2 sensors on the manifold.

 

There are 2 pre and 2 post, correct?

Gonna be an expensive day at Autozone

 

wrong, on you car, there should be a total of 3.

2 on the mani
1 on the cat

 

Awesome, thanks for the clarification!!

I guess for now I will replace the one that is definately bad, the one on the cat, and replace the others in the near future.

 

For $30-50 more you could have gotten a more reliable and durable factory original replacement oxygen Denso oxygen sensor and not needed to bother with the wire cutters/strippers, electrical tape or heat shrink, solder & iron to install it.

 

I've been driving with mine bad for a good 5,000 miles. I can tell no difference. I plan to replace them soon anyway. The dash lighs on bother me more than anything. . .

 

Sorry wrong thread. . . My apologies.

 

True, but instead of buying the OEM one online for $87 and buying the Bosche locally, you have an easy way to return it and get a new one if it soon goes bad again (referring this situation to the O2 sensor in the cat going bad, due to the cat itself going bad) In my situation, I got the check engine light code 28, for my O2 sensor in my cat. My car has 184k miles on it, so there is a chance that my cats have gone bad, causing my O2 sensor to go bad as well.

See what I am getting at?

 

@ the time I was planning on going turbo, so that entire manifold & the sensors were going to go out the window. I didn't have any problems w/ the bosch sensor -- I got about 320 on a tank of gas, reving it up quite often on mostly city driving. On straight up highway driving, I'd get around 380-400+ on a tank.
My car was rear ended and totaled after driving 12,000 miles on that sensor -- No CELs, no funky idles, misfiring or detonation. I also drove all the way across the US with it -- Boston to Malibu.

would I use a bosch sensor again? proably not. Did it work completely fine? yes.

 

What are the chances that my bad O2 sensor also caused my cat to go bad? Should I maybe just have the cat removed and have the O2 sensor put into a custom midpipe, so I dont ruin another sensor on a bad cat?

 

weak 02 sensor = higher fuel consumption = more concentrated hydrocarbon emissions in the exhaust stream before the cat = hgiher temperates inside the cat = quicker wear out of the cat

Solution? Change the 02 sensor at around 100,000 - 125,000 miles* BEFORE it gets real lazy and use a top quality factory original sensor instead of a imitation quality sensor like a Bosch.

*Typical drivers, but exclusive highway drivers who keep their engines well tuned up may go 150,000-200,000 miles before the oxygen sensor gets lazy.