Is there only one mire going to the knock sensor? If so I assume it reads impedence between this wire and chassis ground. am i correct?

 

There are two wires for the knock sensor, but only one actually leads to it. The other wire is grounded to a place on the upper intake manifold way before the area where the knock sensor "lives" (middle area).

 

This is whY I am asking. I am getting a 0304 code. Knock sensor failure. I do not have enough money to replace it right now. So what I did was, I took the single wire leading to the knock sensor and wired a 470K and a 47K resistor in series. This gives me an impedence of 537K +/- 5%, A factory KS reads 540K. Anyway. I connected the resistors to the KS wire, then grounded the other end to the battery. After i cleared my codes and cranked the car and ran it for about ten minutes and then checked codes again. I got a 0505. All clear. I have quiet a bit of electrical saavy, and everything in my head tells me this is a perfectly acceptable method to use for a week or so, but I just wanted to make sure there was not something really strange that I am not taking into account.

 

Nah, you're cool for now.

 

i was wondering this as well. From what I have been hearing a knock sensor is a highly highly long life time item. As you all noticed, it seems that their are grounding problems and electrical problems with a lot of nissan sensors MAF, TPS, etc. I wonder if there is some wiring woes to the knock sensor opposed to the actual sensor going bad. All it takes is a bad ground, bad wiring to get the code, not the actual sensor being dead. Any comments? I'm not that electrical, I'm an ME in training , but I have been thinkin about this for a while, but the lead going to he knock is extremely long with no sub connections so i cant test out my theory.

 

In my experience, if the ks code is the only one you're getting, change the ks. I spent a couple of months, mostly because I was broke, testing, retesting, grounding, etc...
Changed the ks. 0505 all the way!

 

0505 24 hours later!

 

I wanna do this, I dont know **** about electrical. Is your knock sensor still functioning? or have u completely bypassed this. cuz if thats the case, i would be interested in doing this as well. I use 93 octane and dont plan on doing any type of nitrous/boost setup. Id rather not spend the money. Explanation please, and pictures if possible? Thanks man.

 

Plurco, did you notice if some of the power has been restored to your car, or is this "mod" just to get rid of the KS CEL code?

 

This is very interesting.

What would we have to do to competely illiminate the ks? If we run 93 octane and are not boosting or spraying we dont need the d@mn thing.

On my DSM I can just ground it out. Is it the same with the Max?

 

I want to do this mod because I keep getting the knock sensor code, even thought i bought it new from teh dealer a couple of mnoths ago. Maybe if I do this mod I wont get the code and maybe even the engine will stop functioning in safe mode or retarded timing mode.

 

I was in the process of changing my knock sensor but found some problems (was throwing a 0304 code). I tried testing the resistance of the sensor, but it only showed zero resistance.

I noticed the ground wire coming out of the KS wiring harness was plugged(with a blue rubber stopper-the right lead coming out of the KS). It seems as if the ground wire was cut and taped off ( I couldn't see this initially because the wire protector...that hard plastic accordian tube that covers the two wires was wrapped around.) I haven't seen another maxima to compare.

Are you guys saying the ground wire from the knock sensor should be grounded somewhere? I think someone rigged up my knock sensor. I will have to hit the junkyard tomorrow to see how this knock sensor should be properly wired. Though, does anything I've described, seem completely rigged to you? As in, someone tried to "fix" the KS code?.

And to answer someone's question about noticing differences in performance with or without a knock sensor, is that I noticed a huge performance difference when the ECU doesn't respond to a KS code. I found this out by unplugging the MAF and Intake Air Temp sensor....then starting the car, turning it off...reconnecting sensors, then starting, then driving the car. For some reason, the ECU forgets about that KS code temporarily. I dunno why, but it does. This is when I noticed how my maxima SHOULD run, and I investigated further as to why. It improved the low-end performance tremendously (as well as the shifting....I guess the ATranny is geared to respond (change gears) to certain power levels or something).

 

izzy, to answer your question about the ground...the ground is not suppose to be connected directly to the KS. Only ONE wire is connected to ehe knock sensor, where the ground is routed to a point ont eh upper intake manifold, so your KS seems to be ok I think. I want to know exactly what you guys did you kind of "bypass" the KS. I have a KS code (which is ****ing me off because I bought a new one a couple of months ago) and I have no idea why its going off. My low end performance is horrible, not smooth at all, but my high end is pretty good. I also have bad idling, liek there is a big difference between my drive and revers positions and my nuetral and park positions. When I'm in P and N, it feels so smooth and calm...but when in D or R, you can feel slight vibrations, and the idling bouncing and car jerking. Let me know, PM me if you want. Thanks

 

so can we get a write up and maybe some pics? this would be greatly appreciated. I know this isnt the correct way to fix it, but for someone who uses 93 octane every tank, and is a poor college kid, needs this to be done. Thanks!

 

The way to bypass the KS is to insert a resistor into the harness. The nominal resistance for the KS is a little more than 500 kOhms. The closest I could find at Radio Shack was 470 kOhms (that's 470,000 Ohms for those of you who failed math class).

Just unplug the harness and insert the leads of the resistor into the plug. I wrapped mine up in electrical tape just to keep water out of the connector. I have not gotten the 0304 code or any knock since doing this.

 

mzmtg, I have a question, when you had teh KS code...did you timing get retarded (considering thats what the engine does when the KS code goes off to prevent damage)? If so did it stop now and go back to normal? Let me know thanks.

 

I'm assuming this is going to be something rather basic and easy, but just for ***** and giggles, anyone have pics?

 

the way I did it was like this
groung------>470k resistor---->47K resistor----->knock sensor wire.
I gained a full second in the quater mile. I kid you not.

 

interesting. So I would just take the leads out of the knock sensor, then attach these in series? Arent their three leads going into the knock? Thats why i keep askin for pics. So clueless with electrical things.

 

during the process of unplugging the KS I pulled the wire out of the plug. DOH! anyway there is only one wire in the plug. I wired the two resistors in series then attached the KS wire to one side and the other to chassis ground.

 

The black wire in the harness is a chassis ground. I just stuck the leads of the resistor into the plug.

 

Where did u get the resistors and how did u wire them in series? I thought Plurco spliced the wire and did it that way? So you can put the lead into the hole? Interesting.....Thanks for some reply in advance.

 

Now we come to the ultimate question. Whats the risk. By me always using 92-93 octane, are there still chances of pinging or detonation? Just checking. You know how it goes though, all i need is one person saying, no problems here and that gives me enuff confidence to go ahead with it. I dont want to spend the $ for a new knock, and i think it will just go bad again soon anyways. Maybe when i have like 200k miles ill put one back in.

 

Question......I'm in Cali and the highest grade octane we have at the pump is 91. How do I get a higher octane level?

 

If yoy have a KS problem,is the MIL light on ? My car hesitates a bit bet ween 1ooo-1500 rpm,no matter what gear Im using...Once a bit higher RPM is fine...Anyone with the same problem ? 99 Gxe 5 sp. and 42 kmi,and no check engine light is on...Im pretty good under the hood,but have no ideea where is the KS located...

 

I just changed the KS in my car. The engine light does not go on for just the KS. I had hesitation in the lower rpm range but now... When I pulled the KS out, I got zero resistance. I gave it a bang on the bench and the resistance read 600 K ohms? It must have been working half a#s. Stand by the drivers side fender and look in the valley under the intake manifold, you should see the KS with a wire connected to it.

 

I'm in Cali too and use 91 octane, you probably don't need higher, but there are "octane boosters" available at local auto parts stores which should raise it a few points. Anyone else paying 2.39 for premium 91?

 

this is what im saying, i think there is wiring issues as well as construction issues on the KS. I just want to avoid it and bypass it like this using the resistor, unless i ever boost or juice it I really got no need for it.

 

So the only wire leading to the knock sensor is an actual ground? I thought there were two wieres at first, but then they split, one heading to the knock sensor, the other to a chassis ground on the upper intake manifold. Let me know, because it seems liek you are takinf teh wire that goes to the KS and putting 2 resistors in between it..and then grounding that same wire. ????

 

my knock sensor is F(_)CKED! I tested the resistance by unplugging the plug to the nearest connector. (I think its F121 or something) And i got a 1Megaohm reading for some odd reason....then when i turned the car on i was still testing it and it jumped to 2M ohms....what the **** is going on? Can someone finally fill me in on how to check the damn thing properly cause this is just ridiculous. Im about to go at my intake manifold with a jackhammer....Please save my maxima's life. Thank you.

 

WOOOOOOOOO HOOOOOOOOO!! 0505!!!

 

What did you do?

 

I went to Radio Shack and got the resistors. I saudered them in series. Then, I saudered a wire (the same type of wire you would use for a remote wire on an amp) to one end of the resistors. Next, I stripped the end of the un-saudered wire and clamped a small ring. The ring with the wire, I grounded it in the same place the original KS is grounded. On the other end which is the other end of the resistor, I folded over and put it in the KS harness. I reset my ecu and drove around for about 20 mins and then checked my codes. All clear!! It seemed as if I could feel the difference right after I did it. Back to the part about putting the resistor in the harness...it seemed to not be as tight as I wanted, so what I did was clamp this thing (I dont know what the proper name is but you use it for speaker connecting and its flat) on the end of the resistor and cut it in half down the middle so its still long, not across. It ended up being just about the width of the inside of the harness. I then put it in and now its nice and tight until I get my new KS.

 

Hmm I wish there were pics, this sounds a little confusing to me, only because I never really worked with resistors, and dont usually sauder much. =( I so want to do this

 

Neither had I. Once I did it, I thought to my self, "that was easy!". The hardest part to me was understanding resistors and series wiring. I looked that part up on the net, then it all came together. It basically means in a straight line to make one long resistor. After that, it was all about plug and play!

 

Man o man, these are the kind of threads that have saved my As$ . Im going to try this 2-morrow and do my very best to post pictures.

 

Well, seems like so far we got a winner, lets make sure we dont forget who's idea this was. Good job plurco, hopefully this will become a sticky. Obviously we know what the negative affects are, so just realize what you are getting into when u do this. If you use cheap gas, or plan on juicing or boosting, this might not be so safe. just my 2 cents. I plan on doing this tonite, I will take some pictures if i do it correctly.

 

In that case, I'll take credit. Unless someone wrote it up earlier than 8/19/02:

http://forums.maxima.org/showthread....n&pagenumber=2

(middle of page 2)

 

I have to give all the credit to MZMTG. He pioneered this. Remember this is just a patch not a fix.

 

haha my bad