Post-cat O2 sensors - 986 Forum - The Community for Porsche Boxster & Cayman Owners

landrovered · 08-13-2010, 07:37 AM

I will put this out there for your consideration.

The pre cat sensors do the heavy lifting for the fuel injection system, they set the overall rich/lean mixture for the engine. If a pre-cat sensor was to fail on my car I would replace both.

The post cat sensors are only to confirm that the cats are working. They are not nearly as important as the pre cat sensors. I would replace them one at the time.

Also the only thing that makes it a "Porsche" O2 sensor is the plug (connector). They are bog standard Bosch thimble type O2 sensors and if you are willing to do some soldering you can buy them for $39 but you have to solder your Porsche plug to the wires.

Frodo · 08-13-2010, 07:52 AM

Quote:

Originally Posted by landrovered

I will put this out there for your consideration.

The pre cat sensors do the heavy lifting for the fuel injection system, they set the overall rich/lean mixture for the engine. If a pre-cat sensor was to fail on my car I would replace both.

The post cat sensors are only to confirm that the cats are working. They are not nearly as important as the pre cat sensors. I would replace them one at the time.

Also the only thing that makes it a "Porsche" O2 sensor is the plug (connector). They are bog standard Bosch thimble type O2 sensors and if you are willing to do some soldering you can buy them for $39 but you have to solder your Porsche plug to the wires.

Makes sense.

I thought about doing the standard/generic route but got lazy and ordered the plug-and-go ones, though I am planning on putting them in myself. It's not too tough, is it? I don't have the special 22 mm wrench...how hard is it if one uses an adjustable wrench??

BTW, I've read that you should crimp NOT solder. Don't know why...or even if it's truly an issue.

landrovered · 08-13-2010, 08:15 AM

It does not require a special tool, it is butt simple as long as you remember to unplug the sensor before you try to remove it. Also - DO NOT PUT ANTISIEZE OR SEALER on the sensor when you re-install, the chemicals can contaminate and ruin the sensor.

boxzilla · 08-13-2010, 12:02 PM

It is not a difficult job...the only 1 i had trouble with was the post-cat, passenger side ..... it's a tight spot and the wire and head unit have to find their way around a number of obstacles.

I would recommend getting the right wrench as it may be frustrating to do otherwise. Try Harbor Freight is you have one local, or since it is only 1 wrench just go to Sears.