To give you an idea of how busy I am, I swapped out an O2 sensor on Sunday and am just now starting to write the text on it three days later!  The reason for writing this procedure is to take away the intimidation factor behind replacing the O2.  It's easy.  It's VERY easy.  But, right now it's restricted, looks like it requires crawling on the ground and it just doesn't look like much fun.  It's maintenance and it needs to be done and it's not that hard.  Is your car sputtering?  Stalls out of the blue and then starts back up again?  Has it been 50,000 miles since the last O2?  Then it's time.  Let's go.

The O2 sensor has the job of "testing" the oxygen levels (thus the name) in the exhaust and telling the computer (even the very basic CIS computer) what to do with fuel pressures and thus air/fuel mixtures.

The first thing to do is to locate the wire that connects the O2 to the harness.  One female spade connector with a boot over it is all that attaches the O2 to the harness.  This interface is located right below the cold start injector in the nestle of wires that also includes the lambda sensor port.  If you can't find it, don't sweat it.  You can't see the O2 from this side of the car so you can proceed to the next step and find the O2 sensor and trace the wire back over here and disconnect it.

Going to the airbox side of the car, pull off the air tube going from the airbox and pull the boot off of the throttle.  This will give you plenty of access to the O2 in the exhaust manifold below.... even if you have a Neuspeed stress bar in the way.

Reach down into the engine compartment and pull the wire out that connects the O2 sensor to the wiring harness.  Slide a 22MM socket over the wire.  If the socket can't make it over the wire, go ahead and cut the wire, but you might want to get used to fitting the socket over the wire because you're not cutting the wire on the new one!  With the socket firmly over the O2, grab onto the socket with a pair of Channel Locks and unscrew.  In a prefect world threads are greased and are not overtightened, but if it turns out that this puppy is not coming out with a pair of Channel Locks then I see know choice then to cut the O2's wire off and put your socket wrench on the socket and pray that you don't bust a knuckle on the exhaust manifold!

After the old one is off, feed the new O2 sensor's wire through the 22MM socket andput the O2 into the exhaust manifold.  With the little "pig tail" coming out of the back of the socket, it's going to be impossible to tighten this puppy down with a socket wrench, but that's OK.  The Channel is all you need to get this thing as tight as it needs to be.

Pull the socket off, run the wire over towards the passanger side and connect the spades together and voila!  You are done.  On a side note, I like to put a little grease on the wire connectors.  Also, there is no need to put grease on the O2.  The Bosch O2 I bought had ample anti seize on it's threads.  Fire the car up and double check your lambda with your dwell meter and away we go!


 
 
 
 
 
 
 
 
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