After reading much on maxima.org and other sites regarding the infamous knock sensor replacement procedure for my 95 Maxima, I ordered a new KS from Nissan and installed today. Many threads and sites suggest if the resistance of the KS measures somewhere around 550-560 it should be fine. After retrieving my old KS from the engine I ran it upstairs for testing on my ohm meter and to my surprise found it to read 556. I tested the new sensor and found its resistance to read the same. I am led to believe resistance is not the tell all of a bad knock sensor because mine was without a doubt kaput!!! With the new one in on my first test drive right after installation I noticed an immediate difference in the lower RPM range only 5 minutes into the test drive. Further, my ECU no longer has the bad KS code in it. Has anyone else had any experience with this?

 

It's been said numerous times, mostly by me, that the resistance doesn't really prove jack on the KS. If it's 0 then of course it's dead but it can be 560 and around there and still be as broke as MC Hammer. I checked mine it had 550ohms but I had a code when I checked the ECU I would reset it over and over but the code came back. Got a new KS had same resistance but no more code.

 

has anyone open a bad ks to see whats inside i bet soemone with good knowledge in electronic engineer can custom make one for a few bucks

 

I have thought of that too, just don't know how to pry open that oyster. Anyone???

 

i might do it but not buying the ks until end of next month or so so if anyone has a bad one may try to open it a take some pics

 

TVerner, did you use the motorvate method?

Namely a 12 mm flex socket (Craftsman), and maybe a 14 inch extension?

The 12 mm flex socket i got from sears seems to endlessly swivel, and won't lock into place.

I am curious as to how you changed yours.

 

The KS is pretty much a PIEZO device. It's sort of a microphone that listens for a specific frequency and retards the timing when it hears it.

 

Yes, I did use the motorvate method but my swivel is a mastercraft brand and does not have as much play as you made yours sound. Tighten the hex nuts on your sears swivel so there is not as much play or get a new one. If I could give any advice it would be to prop a small diameter flashlight in some of the hosing at the KS entrance so you have both hands free and it shines right into the KS cave. Next I would advise anyone doing this to feed the extension and socket in the KS cave by hand without it being attached to the wrench. Make the swivel at a 45 degree angle before going in and approach the nut from the left side and slowly turn the 12mm and swivel over so that it seats right on top of the nut. Once that is in place, gently attach the extension to your wrench. It is important to approach the nut from the left side because there is not enough room on the right side for this maneuver. Good luck.

 

Side note: the KS resistance is 550 000 ohms, or 550 k ohm, not 550 ohms.

 

I tried this with a 1/4 inch drive and broke the flex socket. It was pretty lamely constructed. Went back and exchanged everything for 3/8" with a 10 " extension and that did it.

Also........
I could not fit my hand in there (not even close) but I got the KS out and the bolt using the socket and the wire (slowly and carefully). After much head-scratching about how the hell I was goin to get the KS and bolt back in there (and threaded) I ended up putting a glob of silicone in the socket then inserting the bolt into the socket.....So it would stay there. I then put the KS on the bolt and using the wire and the extension guided them both in there and after maybe 3 minutes found the hole and threaded it in and tightened it. Once tightened you can obviuosly pull hard enough on the flex socket to break the silicone bond and remove it leaving the bolt threaded. I then just tightened her down and I was good. So a little variation on the bloody stump technique, minus the bloody stump.