is it time to change the knock sensor

[silvia lover]

just wondering is it time to change the knock sensor b/c i got the code 34 (but it happened before and it just gone itself) and my car had 150k miles on it. I looked at the engine bay and it was a really tight spot to reach. so I asked the nissan dealer and they said it will be 50 dollars to put it on and around 180 something for the sensor. I don't know guys, should i do it myself so i can save myself about 70 dollars? or let the dealer do it?
man, things ain't cheap this day comes to car parts. thanks for looking.

[twitchy]

do you need to change it? Engines only knock when you use a certain octane gas or overrevv them dont they?

I always try and change things myself, and when I take it to the dealer I watch them do it for future reference

[silvia lover]

i have no idea, b/c the check engine light came up while i was driving last week(don't know what was going on but it just lighted up while i was waiting the signal). And i found out that were the o2 sensor and the knock sensor. I do stuff myself either but the location of the o2 sensor just a biatch to reach. And the wire and the knock sensor adapter were attach really good. I have no idea so hope anyone can give any idea will be great. to twichy: I only filled the super unleaded from chevron since i got my car. so it might not be a problem (who's know, maybe they trick me or something). I can actually watch they while they working on our car? i have no idea about that though. if that's true, i will watch them till the end and make sure things go well. hehehe. btw, thanks for the reply.

[sykikchimp]

knock sensor, and 02 sensor are both very easy to replace. You have to get a special socket for the 02 sensor.. wither that or a big 7/8's wrench. you can get both those parts at autozone much cheaper than Nissan.

DIY and save some money.

If you think you might be experiencing knock, get a timing gun, and check your timing ad make sure it's in check. I run +25 degrees and don't have a problem with knock on 93 octane. Factory is +20 +/- 2 degrees

[silvia lover]

but how can i get to the knock sensor? since it is between the intake maniford and the sensor is kinda deep inside there(autozone charge 269dollars for the sensor and the dealer charge it 188 dollars >_<) so what kinda tools do i need to reach it and hold on to the wire(because the wire looks really short and won't be able to pull out easily). thanks for the reply sykikchimp
but more details will be great. thanks.

[kalieaire]

to remove the o2 sensor, all you need is a crescent wrench.

for the knock sensor. read this article on 240sx.org

http://www.240sx.org/faq/articles/knock_sensor.htm

[sykikchimp]

damn.. thats has to be the first time I've ever seen anything more expensive at Autozone, than at Nissan.

Anyways. Good luck.

[mrmephistopheles]

uhmmm
not to knock you guys (pun intended), but replacing the knock sensor is NOT easy. I replaced mine (as it was cracked and not working), and it took my about an hour of work to replace it. Granted, this was in my early days of wrenching, but I remember it vividly.. Anyway, I bought my replacement from a '96 motor for $30 in a junkyard.
You know where the knock sensor is, yes?

[sykikchimp]

ok, so I was exagerating a bit. It's still a DIY job. just cause it's hard to get to, doesn't mean it's complicated.

[Mark95TT(ATL)]

Originally posted by twitchy
do you need to change it? Engines only knock when you use a certain octane gas or overrevv them dont they?

Just wanted to clarify: from what I gather, when you get a code 34, it means your ECU detects a short/open in the knock sensor circuit, e.g., your sensor is bad.

If your engine is actually knocking for some reason (and the knock sensor is functioning correctly and detects knock), the ECU will compensate by retarding the timing, up to 3000rpm at least.

If your sensor is bad and you're getting a code 34, you do need to change the sensor because your ECU is probably getting bad values and retarding your timing. Your car will probably feel sluggish until you replace the sensor.

Someone correct me if I'm wrong.

[silvia lover]

i have no idea what was going on. But after i drove to school with replacing the knock sensor in mind. The battery died for the short wires of the headlight(it just on for no reason and can't turn off). So i got a jumped and my car run again, but the code was gone :confused: I like what the hack, since my car was over my mechanic to chase the wire down. I have no idea the light was gone for good or will back later on (how can i check the knock sensor and see it's in good shape? or will the dealer do it for no charge :D ). Anyways, thanks for your guys replies and 240.org is really handy when it come to common problems with ours 240sx(and i did read the article before i post it, but it didn't say about check the knock sensor beside read the ECU code).