Originally Posted by phenryiv1

How to Change Knock Sensor http://www.motorvate.ca/mvp.php/507

Originally Posted by gansemer

Two good article on KS replacement:
http://www.skippynet.com/maxima/knocksensor.htm
http://www.motorvate.ca/mvp.php/507


Modifications to the Skippynet method

The article suggest using a 14” (or longer) ¼” socket extension to reach the KS retaining bolt. I found that using a 9” extension made it much easier to get the u-joint onto the KS bolt. To save money, I used two 3/8” drive extensions with a 3/8 to ¼ adapter, a ¼” drive u-joint and a ¼” 12mm socket (most of which I already had). Skippynet suggest using a 12mm flex socket, but being cheap I used a separate socket and u-joint so that I would have a more useful general purpose tool left over than the 12mm flex socket (better yet, I borrowed the u-joint and saved another $8). A 3/8” u-joint is a slightly bigger animal and in my opinion would make it hard to get the socket onto the bolt. It was not at all difficult to loosen the bolt using this setup. I had also borrowed a 16” extension and found it very difficult to get the socket onto the bolt head (I gave up after about 2 minutes, so it probably could have been done).

Once the bolt was out, I used a magnetic pickup to retrieve it (and eliminate the possibility of dropping it into the engine cavity where as you will find out soon, is not a very friendly place). With the bolt removed, you can pull the knock sensor out of the cavity by the harness and replace it. Next, I put the bolt into the new KS and used a small piece of tape to hold it in place while I stuffed it back into the engine cavity (again to eliminate the chance of dropping it in there).

Now the difficult(ish) part: I don’t see how you can locate the bolt into the hole and get it started without stuffing your hand under the manifold. Others have done it using a claw type pickup to position the bolt so no harm in trying. If you have very large hands, you might try enlisting a girlfriend, your mom or a small child as others have done. I was able to get my hand in there and get the bolt hand tight, then it was just a matter of using the 9” extension/u-joint setup again to do the final tightening. Your hands will get cut up a little doing this, but the term “bloody stump” that gets thrown about is quite an exaggeration.

I was able to replace the KS in both cars in less than 1 hour including test drives using this method. Post installation I got back the power of my VQ and gas mileage increased by 2 MPG.

The real key is using the skippynet socket extension method to crack the bolt loose. Once you have jammed your hand into the engine cavity you will realize how difficult it would have been to get a wrench on the bolt and loosen it.

Originally Posted by phenryiv1

If you ask a question and the answer can be found in the FAQ threads, your thread gets locked.

Originally Posted by ThreePointO

.. great. is that something i can still do myself or am i getting into crazy stuff?

Originally Posted by ChrisMan287

Changing the KS or harness are both DIY jobs. Search and find the write-ups.

Originally Posted by BEJAY1

I started by testing the ohm resistance between both terminals at the harness connector and got nothing (1). Tested the new KS directly and got 550ohm which is in spec.

I pulled the old KS off the harness and it tests similar. It too registers similar good resistance. Testing at the harness comes up nothing (1).

FSM says at the harness there should be 500-620ohm between term2 and ground. Haynes says there should be contunity between the 2 harness pins. I'm getting neither. Could my harness have a short? Or are these tests not accurate because of the single wire/ground design?

Originally Posted by pmohr

The Haynes test doesn't really make sense because of the single wire harness. You should be getting a resistance measurement to ground, though. Sure you're testing the right pin?