KilJim

It'll be hard to even get PB on the bolt, it's too far hidden
It isn't bolted in too hard anyway, i don't think you need the PB as long as you get proper leverage

KS code will be gone after you replace it
Only O2 sensor code remains

Shift_Nismo

iTrader: (9)

Not if the subharness is bad too. Also, other codes can trigger the KS code.

EDIT: So I had the codes erased, and when the light came back on the next day, only the O2 Sensor code was left. I don't feel too much difference in my car, so maybe I will feel this big difference when I fix my O2 sensor.

TreizeRXH

Speaking of o2 sensors, a few months ago my CEL came on. I ran to pep boys, checked the code and it gave me rear o2 sensors, bank 2. I didn't have money to do anything about so I just kept driving...but then the light went off. It then proceded to come on again a few weeks later, then went off again, and has been repeating this pattern ever since. Any insight?? Is this the computers way of telling me to replace the damn sensors?

98Maximo

Little advice for those looking to change the sensor:

If you have a regular sized wrench, it may be too short to get comfortably on the bolt head. A U-Joint makes it 1000x easier. I was able to take the bolt off no problem with that and an extension.

Putting the bolt back on was a much bigger pain in the ***. To help hold everything on, I put duct tape IN THE SOCKET on the wrench to help hold the bolt in while I tried to lift it (and the KS) into the proper spot using the U-Joint and extensions. That was the only way I was able to get it back on. Once the bolt starts going, then attach the wrench to the end of the extensions and tighten it fully. At that point the duct tape in the socket end will let go of the bolt and you can pull it all out.

I reset the ECU (the same as checking for the codes twice without a break in the middle) and I noticed a pretty substantial difference. Engine seems more eager across the whole rev range but particularly about 3k. Really pulls much more than it used to. Definitely a fix worth doing.

TravisCadello

so the knock sensor can cause bad gas milege and weak lower rpms?

cdmapro

many on here claim so. but in my experience it didn't make a difference in power or fuel economy. that's because I don't drive my car hard. the KS only makes a difference under hard acceleration. so if you drive hard all the time you might see some improvements.

pocholin

HELP!

This thread is great, I replaced my knock sensor...but there was no cable/harness connected to my sensor...I guess now I know why the light came on!
I looked around but couldn't find the cable at all, does anyone know where does this harness starts at so I can trace it???

Thanks

pocholin

I've been with the knock sensor disconnected for the past 10K miles, my mileage (mostly freeway) is 25-26.5 mpg (~420-450 miles per tank) , don't get past 75 mph much. Can't complain, don't think it will cause bad gas mileage.

The Wizard

iTrader: (43)

The KS harness is only about 12" long, so look for a nearby plug that isn't connected to anything.

mikeg75

I just had new spark plugs and valve cover gaskets done on my 95 SE 5 sp, and I was expecting the car to have a little more kick but it seems the same. I have no CEL code and was wondering whether just replacing sensors like the knock sensor without diagnosing a problem, would be worthwhile?

Last year I replaced the EGR Solenoid, the ECTS, and MAF sensor. Of the three, the only one I was getting a code for was the EGR solenoid. Since then, the only other code I've gotten was a rear O2 sensor (bank 1 sensor 2) and all the while, the car has run fine, but just doesn't have the pick-up that I remember. My mechanic cleared the O2 sensor CEL and it hasn't come back on in the week since the spark plugs and gaskets were replaced.

Does anyone have any feedback about just swapping out sensors like the KS? Thanks!

eddie982

iTrader: (10)

If you've never replaced the ks before, it definitely makes sense to do it. I did mine and see a noticeable difference in power.

mikeg75

My KS was replaced at 138,000 (4 years ago) and looking back through my records, I paid out the a$$ for that work, 170 for the part and another 200 or so for labor. That was before I had found the .org and also when I lived in an apt and had nowhere to work on the car. If I have 169,000 on the car now, maybe the slight loss of performance and lower gas mileage is the O2 sensors? Again, no CEL codes, so I'm just grasping.

talisman311

99 cali-spec here. You've gotta be kidding me. How the F am I supposed to get to this f*****?!?!? Just did my rear valve cover gasket and then saw the KS and all the BS I have to remove to get to it.. Seriously Nissan???

Ok done venting.

illmortal

lol... I have no idea how you guys are having access to the KS... I believe the car was originally from NY (previous owner lived in NYC) and my KS is right underneath the intake manifold. I can't even fit my hand in there to put a socket into it... much less have enough room to loosen the nut. Looks like I'd have to remove the intake manifold in order to inspect the KS.

99sagelimited

I have a 1999 Cali spec and changed my knock sensor a few weekends back. It can be done without removing the intake. After 3+ hours, here is what I learned:

1. Remove the intake and loosen the bolts to the swirl valve. The swirl valve is the canister that is basically blocking you from getting your hand under the intake. Once lose, it gives you a little more room to get a socket in there.

2. I used a universal 12mm socket with 2-6" extensions to access the knock sensor bolt. This will take some time to get lose, but be patient, it will work.

3. With the bolt lose, I used a telescopic magnet to pull the bolt out, and again to slowly pull the knock sensor towards me. Once the knock sensor is close enough, you can grab it with needle nose pliers to get it all the way out.

4. This would be a good time to check your harness, but otherwise switch out your new sensor.

5. To get the knock sensor back in, I first carefully aligned it over the mounting hole by pushing/pulling it with the telescopic magnet. This was actually pretty easy for me to line up.

6. I again used the magnet to get the bolt in place through the knock sensor and into the mounting threads. This was pretty easy too.

7. Use the universal socket again to tighten up the bolt.

8. Re-install everything else.

If I did it this way to begin with, it only would have taken me a half hour or so. I was really close to removing the intake. Don't give up, it can be done.

talisman311

Thanks for the advice. I ended up removing the lower intake manifold, fuel rails, etc. to get to it. I'm just glad I'm done at this point.

KingZeke

Could the KS be piggy backing on the P0306 code? From everything I read, it sounds like the KS could piggy back on just about anything. I was thinking of changing the coil and then having the codes cleared to see if it still comes up. What do you all think?

prodigy401

thanks, just changed mine recently, my old one was so busted

blocster

Easy I think not....Maybe if you have small hands.

illmortal

Seriously. I can only feel one side of the knock sensor with my finger tips... I'm trying to figure out if it has a crack but I can't reach further to feel the other side -.-

KingZeke

This thread was a huge help. I saved time and money and now the car is running great!

Echo247

Hey guys thanks for all previous comments I just changed my KS over in lass than 10 min start to finish and I would rank my self as a novice!!
Although I must say give the ratchet a go first if you have one mine worked a treat had it off in less that a minute!!!
12mm socket, universal, 2x 150mm extensions to the ratchet.

Good luck.

JagerBlunt

iTrader: (1)

As a Mechanic I must say these wrenches are a must have. I have the SK ones which are reversible which is a great feature, if you have ever backed a gear wrench up against something you know what im talking about. the swivel head and long length are great to get in those hard to reach places and give added torque and would make this job AND ALOT MORE TO COME easier. i use these wrenches more than any in my box.

GRNMAXDMON

iTrader: (1)

i use these all day everyday on BMW's and the SK's non swivel are awesome when doing an alignment on BMW's, makes my job a whole lot easier.

nickyleadfoot

After much difficulty I managed to replace my knock sensor in my 99 maxima se(cali-spec). After a few days my MIL came on(which had never before, ever) and I'm getting a code for 1004(swirl valve control solenoid) and now the knock sensor again(the knock sensor code had cleared itself about a day or so after replacement). I only removed the air box to get to the sensor and I'm pretty sure that I've re-connected everything correctly. I haven't been able to find much information on this particular code and was wondering if anyone had any ideas? This was such a tease because I thought it had gone great and my hard work paid off. My engine performance was back to normal for only a few days and now it feels like it did before I replaced the sensor.

LoKeyM4A3

I am so close! On the nut just cant get leverage with 3/8th ext, screw driver, hammer etc... I love a good challenge haha

LoKeyM4A3

Done. Hmmmm, no noticable change in performance. 6 months ago I could smoke my tires no prob, then I got the egr flow code and ks code and here I am with a massive loss of power. Changed plugs, added CAI and high flow cat, changed ks, i cant win lol. Thanks org and all the members who take the time to make these instructional threads. I have completed yet another job and saved lots of money. Big ups org!

nickyleadfoot

Nevermind my dumb a$$ didn't notice that a small black hose branching off right near the swirl valve must have been pulled apart when i moved my air intake assembly out of the way. I pushed it back on and reset my check engine light and so far no more codes

nickyleadfoot

Oh and thanx to all the info on this thread, i couldn't have done this job without all the pics and info. Especially the other '99 owners and their creativity working around that swirl valve. I used a 12mm socket, u-joint and extention, long-flex-magnet, and a bent wire hangar. I got the genuine nissan sensor for 40 bucks off ebay. Nissan wants like 150 for it i think. the dealer wanted 750 for the labor, eff that! I did it better and for free =)

53jimc

SFSG, replaced KS a couple weeks ago, beat up my right hand, though. Still getting IACV code but that's for a different post.
KS code cleared, remains clear and black max got his pep back. Great write up!

GRNMAXDMON

iTrader: (1)

well, you have to understand that once you get things done at the dealer you know you will pay full price no matter what. i work for BMW and the amount of labor that i see is ridiculous since most of the work is so damn easy. everytime i see a v8 5, 6, 7 or even an x5 with oil leaks, we always charge nearly 20 hours for labor and it will take like 7 hours instead. there is always going to be a loop hole. so even though the dealer wanted 750 for just labor just think that the person that was going to work on your car already knows a way on how to do it without removing the intake assembly. us techs already know how to go around it especially with the right tools.

BLACK_03_SE

Nice tutorial! This site is awesome! It saves so much time and money for DIY's!

RedIce

Definitely the simplest method, certainly easier than removing the intake manifold. But that bolt is really hard to start, so I used an extension and universal joint socket. Took too long because I was really trying to be careful - 20 minutes. Also it DID give a code out, so I panicked and went to O'Reilley Auto parts and paid too much for a Knock Sensor, which they didn't have in stock. Then after attending the funeral after switching cars, I poked around eBay and got the idea that I'm always going to check first on eBay...

Maxima1802

Did the eBay part work out?

350zMaximaownr

So, these sensors are available from $2-143$ wtf? Mass production, or quality?

Thanks for detailed write up, will follow when I decide which/what to spend! Any advice is welcomed

J2songz

Just did my knock sensor today, thanks for the help and the bloody hands
http://www.youtube.com/watch?v=B7BGVwFD8AI

nate_man

Here is a youtube video that gives you a step by step. THis is what I used to do mine. I also had a friend (girl with small hands) get the threads started when installing the new one.

http://video.search.yahoo.com/search...b&fr=yfp-t-701

bkbajan

did mine about two weeks ago,used my blue point flex-head ratcheting wrench,gettin it out took some time but the install was really easy. after driving it around..i definitely got some power back,acceleration is so much smoother.

reason for changing was my gas mileage...it was horrible,im yet to do some calculations but by eye-balling the needle i can tell its improved by quite a bit

NickStam

iTrader: (3)

I just did mine and it was such a pain. I removed the intake and still couldn't get my hand in there. I used a socket with an extension & swivel to remove the bolt and to get it back in, I taped the bolt to the socket and dropped it back on. It also looked like I had a few rodent nests in there. I didn't get a harness, but that thing was crispy and felt like it was going to crumble when I was moving it around. Great place for a sensor nissan. F idiots.

queenambeach

iTrader: (3)

Yea, so an hour later and bloody hand and still no success. Will have to try again later..