hangout

my friend just bought a ecu scanner last week, and he tried on my 97 SE.
there was a code come up, but no check engine light on the dash. my car runs fine also.
the code is for the knock sensor..

what's the knock sensor for?
is it hard to change it?

litch

iTrader: (2)

GGENIUS

iTrader: (1)

guess your car dont run fine huh?

mtrai760

iTrader: (19)

The knock sensor detects pre-ignition, aka detonation or 'knock'. When the ecu detects knock it will retard the timing, basically it's going to reduce power to protect the engine. It's a common failure item, beyond reduced power and slightly reduced MPG, it doesn't affect anything. It's located under the lower intake manifold, changing it is more hassle than anything. 1/4" sockets and extensions, a couple swivels, no problem.

hangout

actually the Maxi runs fine.
I was thinking it's a hard to change item also, since my friend told me not to worry as long as the car runs ok.

asand1

iTrader: (1)

Sure, it runs "fine", but you are wasting fuel and missing some HP. $20.00 on eBay, and 20 minutes to install.

surban1

iTrader: (17)

reset cel/mil and if it doesn't come back-don't worry about it; if it comes back-replace the knock sensor. fyi, i'm done to my last dozen genuine oem nissan knock sensor shipped usps small flat rate box for $35.00. here's a link to the classified ad.
http://forums.maxima.org/4th-generat...0-shipped.html

GGENIUS

iTrader: (1)

that was my point, that while you "think" it runs fine, its really missing a little something. and youll realize that once you change your KS.

JvG

I bought my 96 maxima, and drove it for five years. It "ran fine", had good power. One day I saw the knock sensor in e-bay for 18 bucks. I figured it had been 60,000 miles since I bought the car, so I might as well do it when I changed the plugs. I changed the plugs, thn cleaned the K&N filter. Some improvement, not much.

The next weekend or two, I worked on getting the knock sensor out of there. Not an easy job. I finally got the right tools, and learned how to get my fingers in there. Ouch!

The old knock sensor was cracked. After I replaced the knock sensor with the cheap e-bay one, I road tested the car on the freeway. The car has WAY more power, and responds much faster when I hit the gas. The difference is like night and day. I use premium gas, so that the knock sensor does not have to retard the timing.

Do yourself a favor, replace the knock sensor.

So many of us want more power, this is probably one of the least expensive ways to get it. Yes, it is a pain in the ***, (and fingers). Your car will have all the power that Nissan intended when they built the car.

90seven_Maxima

I just priced one at O'reilly's Auto Parts for $119!!

I'll definitely check this out!

Thanks

Spencer5556

iTrader: (2)

Your saying even if you aren't throwing a code, you should replace it?

GGENIUS

iTrader: (1)

he probably, much like the OP, assumed that no CEL meant no problemo.

Spencer5556

iTrader: (2)

So I have no check engine light. and I have checked for codes, I don't have any. Should I replace my KS?

GGENIUS

iTrader: (1)

theres probably someone around wholl say they replaced theirs without a code and without any cracks and regained lost power. so i dunno. although its always handy to have a spare knock sensor on deck incase yours goes.

Zach-R

iTrader: (3)

I dont believe a faulty knock sensor will throw a cel... I never knew mine was bad until my 02 sensor died and then my light came on. Had it scanned and showed the knock sensor was bad also. Was not hard to install definitely worth doing.

Spencer5556

iTrader: (2)

I scanned my ecu and it came up clean. But I'll replace it anyways, maybe ill see some benefit

JvG

In my case, I did not have a CEL about the knock sensor. When I did get a CEL, it was related to a bad speedometer. O'Reillys also told me that I had a bad knock sensor. I did not want to pay 120 dollars for one, so I looked on line.

My knock sensor was definitly cracked. There is no way to know unless you get it out of the rat hole it lives in. Once it is out of there, just put in an inexpensive new one. This is not a fun job.....

surban1

iTrader: (17)

the job of changing the ks was a biatch, so you put in a cheap one?

CallMeThatOneGuy

iTrader: (2)

I never threw a code for the KS but when I replaced it it had bulges in either side like it got too hot or there was something inside trying to get out..... lol but it made a big enough difference for me to be able to tell whilst driving, therefore it is worth it in my book.

Spencer5556

iTrader: (2)

You don't get a CEL for KS, I was saying I don't even have a code when I scan for them.

ryandaiber

i replaced mine not too long ago with an ebay one i got for $7. i bought 2 lol check engine light never came back on after i erased it and car has a bit more power

sislen

My 97 Maxima got a knock sensor ECU code about 3 months ago just before my inspection. I reset the ECU and cleared all of the codes. It passed the state inspection easily.

Now when I put load on the engine I can hear it pinging. I really need to replace that knock sensor. My MPG's are around 18mpg with city/highway combined (1997 Maxima SE Automatic, premium fuel, 203,000miles). Hopefully my MPG's will go back up once I replace the knock sensor. I used to get 24mpg in the city, now I get 17-18mpg in the city. It started dropping after they introduced the E90 fuel.

JvG

My Maxima did not ping at all. I feed it premium gas. As I understand it, the ECU retards timing if it detects ping, like you would get with a good knock sensor, and possibly when regular unleaded is used. It advances the timing if the knock sensor is good.

I may be incorrect with my assumptions. I just reported my experience.

To the person who questioned the logic of installing a cheap knock sensor when the installation job is difficult and painful..... Your logic is very good.

I installed the cheap sensor as an experement. If it made a difference, great. The installation of the next one would go much faster since I learned certain tricks and the use of certain tools.

The guy here who offers Nissan brand knock sensors would be the best and cheapest permanent fix.

My cheap-*** knock sensor is still good after six months and 8,000 miles.

GGENIUS

iTrader: (1)

mine is still supposedly good too, after atleast a year. no codes.