Update Post 20

I have an original primary O2 sensor.

Since it is original, how hard is it going to be to get out? Should I spray it first with some PB blaster or WD40?

I was curious since it is 15 years old, should I replace it as preventive maintainance? No codes, but I have read sometimes it will not read a code if it is bad.

My car is running a little rich and gas mileage is not the greatest.

I had a recent tune up, plugs, wires, cap and rotor not terribly old?

I noticed on aftermarket sites:

Post-Catalyst is the the Primary on the headers?

and

Pre Catalyst is the the one near the cat?


Upstream is?

Downstream is?

 

Hit it with a torch if you can.

IIRC the factory service manual recommends running the engine until the exhaust
piping is hot which can help in removal. Torch works better.

Check that the new sensor is grounded well. Very important that it is for performance sake.


EDIT: Definitely replace the sensor if it is that old.

 

 

Get an O2 socket. Easy work.

 

Pre-catalyst: Before the cat = primary 02 sensor

Post-catalyst: After the cat = secondary 02 sensor

 

Also:

Upstream is?

Downstream is?

 

Pre-cat.
Post cat.
That's how I understood it anyway.

 

What is the deal with Bosch ones, anyone using them? Advance only has those in stock. Plus a little cheaper. but noticed they have 2 part numbers as well for direct fit ones.

Is the up and down stream sensors the same on the 96 civic ex's? Unless the harness plug is different?

 

Never use bosch on japanese cars...or american or korean for that matter.. Bosch is fine on european cars since they're designed with them in mind... Same with Denso, don't use denso on european cars.... Stick with what ever is OEM!!!!

 

I thought that was for spark plugs?

 

Search on Amazon for you car. The Denso ones are a great deal and comparable to stock.

 

It applies to all parts... btw spark plugs are NGK not denso. I've seen many issues when people use bosch parts on a car that calls for Denso and vise versa. People can be so stupid sometimes, like the OEM part is $2 more on a $78 part and they'll still go with the cheaper one (bosch in most cases).

 

96 civic EX

I looked at it today, I can not use a regular O2 wrench it will be too long to fit an will hit the radiator fan shroud. I might have to get a slim socket, you can get to it without removing the heat shield, it is supposed to come off, mine is rusted down, doubt I will be able to get it off.

Also, how do you unplug the harness from the metal tab? I am not talking about the disconnecting it, but one end is attached to a metal bracket.

 

If I can get the sensor off of my wife's DX and off of my EX using one I don't see how it's too long. Cumbersome but not impossible.

 

Maybe some brands are longer than others?

For your EX, did you leave the heat shield on?

Also how do did you unplug it from the metal bracket?

 

Heat shield stays on. I'm having a hard time picturing this bracket.

 

Right where the plug is you can disconnect it but one piece is still attached the piece going to the sensor itself, it clipped on to it some how, but it is so dirty I can't see how, plug I don't want to force it off.

 

The connector just unclips from the bracket.

Is this your set up?

 

Yes that is the set up.

 

Ok, put a socket on it, but it seems super stuck.

Just to make sure I am turning the right way, the sensor is in front of me, so to loosen I turn towards the passenger side right? (left?)

I might have to get a breaker bar, but I am afraid I might crack the manifold???? or break it off in the manifold?

I did spray it with PB Blaster a day before as well.

 

I called bosch about the different part number pertaining to the same part. They said the only difference between the upstream and the downstream is the length of the harness attached to it.

 

That is interesting, I got a denso to play it safe by the way.

 

I went through the same problem with my 97 dx trying to get o2 sensors. Thats why I called bosch. I didn't have denso at my parts store and of course they couldn't help me.....

 

Did you have an issue getting the primary (front one) out?

 

I cranked on it, holding the socket with one hand so it didn't torque, and it came loose with a "crack". Before that it didn't seem like it was coming loose.