I just replaced my axles and i have taken my whole tranny out and put a new one in. my knock sensor is bad and im getting iffy about this whole resistor/high octane fuel thing. i dont want my engine to blow up lol.

im just wondering how hard it is to actually replace the sensor. i did both of the things above without TOOO many problems could i do this?

if theres a scale from 1-10 and the tranny was a 10 and the axles were a 3 where would the knock sensor be?

 

8.............

 

FSM explanation; page EF&EC-21 says this: "The retard system by knock sensor KS is designed only for emergencies. The basic ignition timing is pre-programmed within the anti-knocking zone. Consequently the retard system does not operate under normal driving conditions. However, if engine knocking occurs, the knock sensor monitors the condition and the signal is transmitted to the ECM. After receiving it, the ECM retards the ignition timing to avoid the knocking condition."

Stay clear from emergencies, as most forefathers have done about 100yrs.

KS below -100

 

Read the KS JWT ecu split thread and you can get both sides of the argument.

 

I guess if you rate a tranny as 10 this would be 6 or so


It's just time consuming the first time you do it.


and I would replace the KS and the Harness with factory parts. Just go to the dealer, IIRC the last one I did was $120ish for the KS + Harness. Dont forget gaskets, silicone (rtv), coolant, some cleaner (great time to clean out the intake manifold - CRC Green works great).


Just replace it and be done with it, it's worth the peace of mind. As for the whole resistor/not needing one/etc thing, I don't agree with it. Sure, maybe you can get away with it, but I've learned on a daily driver just leave it factory. It was designed to work that way. Just do the job right, replace it and go. Atleast you will have the peace of mind knowing the job was done right.

 

Nissan statement tells all.

Piece of mind is given from above.

If vehicle is driven by blondie, even 10 KS sensor -engine will be destroyed... = ECU has the [noclue] -bit always high.

Few years ago the "just do it" -slogan was seen all over. I guessed it means floorin if any unusual is heard under hood. Maybe my ign is already too retarded?

I am about to install alarm microswitch to my read bumper: when it drops, dash will flash red, siren will howl

 

I support having a good KS (if there is such thing) if you want to drive daily and run crap gas, however a KS doesn't guarantee that your engine will not blow. Bypassing it doesn't mean it will blow. There are too many other factors. If you choose to not replace it, then you should commit to premium fuel and making sure that your timing isn't set beyond the threshold of detonation. Cars have gotten along for years in high states of tune without the aid of a KS. It was up to the owner/driver/mechanic/tuner to not allow the engine to ping itself to death.

 

just do it.
otherwise you'll always be wondering what should've / could've been

 

The KS, as many have stated, is there to keep the engine safe for daily driving by the everyday person. If you want piece of mind, replace it, it's not hard to pull the intake manifold. However, if you don't replace it, my car is living proof (for now ) that a KS is not necessary.


Edit: This is running premium fuel... low octane + no KS = no engine

 

The knocking, caused by explosion of fuel/air mix, and pre-ignition, which is normal burning, happening too early, are two different things, right? What does KS help to avoid? Knocking. What does it not help to avoid? Pre-ignition. Bad gas, combined with early timing can lead to both and the driver may be totally convinced he experiences knocking and his KS is bad, whereas he simply hears pre-ignition and his KS is alive and well and clueless about what's happening. Am I making sense?

 

That statement is repeated word for word in the EF & EC sections of every manual I have, including the 300ZXTT, 350Z, Q45, A32, A33, A34, Z31T, SE-R cars. all of which run either high compression or turbochargers, requiring high octane premium fuel (minimum 91 octane).

most of the people driving these cars only use 87 or 89 octane because of price, and thus the knock sensor is required for each and every one of these vehicles.

If you want to run the car without a knock sensor and use cheap gas... then you go right ahead. but STOP TELLING OTHER PEOPLE IT'S OKAY TO NEGLECT SAFETY DEVICES INSTALLED ON THEIR ENGINES!!!

Just because you feel it's fine to run against what the engineers at Nissan have designed into these engines to protect them from hard use with low octane fuel and poor conditions does NOT mean it's okay for all situations "if you don't drive like blondie." [/soapbox]

 

I would say that preignition is usually caused by carbon buildup or casting slag which can create hotspots causing the pre-ignition. It can have a similar effect that too-advanced timing can have. Another scenario is that a spike of carbon causing a preigniton and then the sparkplug doing it's job. You get 2 flame fronts coliding with each other. A healthy combustion is a "controlled burn" where as an explosion is not good. At least that's the way it was taught in school. If the KS is working properly; it is "tuned" to pick-up the frequency of detonation. If the ECU gets a signal from the KS then it will pull back the timing to help thwart pinging. The KS doesn't guarantee that a knock won't happen. Examample, The 90's Mazda 929s had probs with top engine noise (pinging) It was not a timing issue but an issue with major carbon buildup. If you have enough carbon buildup in an engine, you can pull back the timing all you want and it's going to knock.

 

I hope you guys don't think you can actually hear all types of knock/pinging right?

 

Thats right, but all knocks and pings will be seen on an AFR readout as a lean spike from a dyno, correct? That was my impression anyways, it probably depends on the number of times the data is sampled too.

 

Brad. Do you run the SAFC? I "think" that can splice into the ks signal and see when it's reading something.

 

problem with that is the occasional ping that can cause engine damage won't show up. for it to be seen on the A/F chart, it's got to happen in many cylinders at once to change the overall A/F coming out of the exhaust for a long enough time to be seen on the charts. (and of course make sure smoothing is turned completely off for it!)

 

I don't have one myself, but I know it can display a knock level, so I'm pretty sure that it does splice into the sensor.

 

Seriously. Ultimately it is up to the owner to decide what they want to do, but the problem is if everyone is saying no no, the knock sensor no big deal, just bypass it then people will just do it without knowing the hazards in doing so. To some of us it's not a huge deal if we blow an engine, to others all of a sudden you've got to do more work than the car is worth or you can afford to get it running again.

It's one of those things where if you have to ask you shouldn't be doing it. In this case it's 'should I run without a knock sensor?' and the answer is no, you need your KS.

 

- Funny how u burn u candle on both ends just seein me copy FSM txt. heh. Its reasonable ppl can decide on FACTS. This is a FACT every one of you want to hide and cry in chorus "heaven is fallin!". I find that weird.

- FSM, Nissan Engineers on KS utilization: "Emergencies..."

- FYI everyone; its better to keep KS up and running.

- Opinion on KS: Disgustin de vils de vice, it will not play by the rules, so I will neither. VGE 2yrs with bypassresistor, cold climate, gas used as anybody with brains would do, before that ears been workin for 3mil km's w/o KS. Heaven will fall down as did for our forefathers (they all died), but not b/c of noKS.

- Sit down, blondies cannot follow this forum, FSM FACTS are no danger fr 'em.

 

Yes, the SAFC-II (and I believe the SAFC) have that feature.


I had one, I've also ran everything from 92 octane at 15* to 87 octane at 20* with a resistor in place. Never did I hear my engine ping and you guys can ask Jeff, I live on a decent hill which allowed me to put a good load on the engine. Funny thing is we couldn't get Davebond007's car past 17* on 92 octane with a resistor before it would ping on flat roads.

Trust me, run the knock sensor unless you like working on your car. I guarantee you after an engine or two you will stop caring about the itty bitty ammount throttle response/power you gain because it's just not worth the risk.

oh and the SAFC-II was configured on a base line 92 octane at 15* with all factory safetys in place. SAFC-II was zero'd out to be absolutely consistant.

 

piggybacks the wire for a reading


only thing you cut are the MAF in and out

 

Isn't that what he just said?

 

I'm happy you think that a cold climate is going to make an engine more prone to knocking/pinging.

You may think it's a devils device, but judging by the prevous statement I don't put much weight into that.

Todays engines are tuned much more precisely than past engines. They can accomplish this by utilizing more feedback from various sensors. A MAF/MAP and IAT sensor so the engine knows exactly how much air is going into it. CTS to know the operating temp, O2 and EGT sensors to aid in adjustment, etc. You wouldn't bypass your O2 sensor, why bypass your KS?

 

VG knock sensor is not equal to the one in the VE
VG has 1 full point lower compression ratio than the VE therefore it's likeihood of detonation is lower.

 

I don't think that some of the posts were aimed directly at me but I would like to follow up on my previous comments and some others. I have the resister in my 92. My engine isn't going to blow and it doesn't ping. However, I agree with some points of both sides of this. As I stated in the other thread, I would not do this mod for a customer and I haven't told anyone on here haphazardly to bypass anything. There are consequences for repeated detonation and yes it can damage an engine. I personally don't think there is a ghost detonation that we can't hear. Detonation is known to be audible and I have never seen or heard anything that supports that there is this very faint detonation that is secretly destroying your engine because you can't hear it. If it is that faint, then I doubt it is really doing major damage to an engine. I listen to my engine and know what's going on. If you are cranking the stereo or have a rice muffler then you may not hear what would normally be audible detonation It's not true that if an engine pings for a second while going up hill that it's going to dump it's bottom out. Repeated detonation will damage or destroy the engine however. I think that 95% of the public needs the KS (Suzy Soccarmom). I personally don't. I agree with Wiking that the KS doesn't play by the rules and I don't want it jacking with my settings. If I damage my engine, it will be because of improper tuning on my part (shame on me) and not because a KS (that probably doesn't work properly anyway) is not in place. As I said previously, I will be the first one to confess if I destroy my engine. I reiterate that the KS doesn't guarantee the elimination of detonation. I also said in the other thread that if you bypass and not follow the rules yourself then there will be consequenses. I'm not trying to be the devil's advocate but be objectionable. I hope that is fair enough. Just so know everyone knows, I would not bypass the one in the 99 because she doesn't play by the rules with fuel grade. I do. Here's my advice...It's proven that a car can run without the aide of a KS without "blowing the engine." The key is [U]YOU GOTTA PLAY BY THE RULES. Many people simply do not or know how to play by the rules to stay under the threshold of detonation. If that's the case the make sure you have a good KS and harness in place. Also make sure the KS hasn't been dropped, otherwise it's no good. Also an O2 and a KS are 2 different animals. (Q) Why would you use an ASP UP when it eliminates the harmonic balancer? (A) Because Jap engines are well balanced from the factory and will tolerate it. You are over riding anything that a Nissan engineer designed when you mod your car. Just because a factory person engineered a component doesn't make it gospel. Look at the crappy factory Y pipes.

To make another point...My 91 NX2 with bolt-ons ran better and got better mileage with good gas. The .20c more a gallon was offset by the increase in mileage. I try to argue this to my gilfriend and others to get them to use the good gas. I haven't checked the mileage in either Maxima but I'm sure the same would apply.

 

i tend to agree with the better gas mileage it seems that im getting WAY better gas mileage with better gas

 

these knock sensor arguments are getting kinda old but i have a simple solution

"if you have to ask a question like this you need one"

how does that sound that way the people that dont use them dont have to defend themselves all the time and we dont have to "give bad info" to anyone

PS ion sensing OWNS the KN

 

Yeah but in my VE, that's 1.5 difference

Still no ping...

 

when I got my car it needed a new knock sensor wiring harness. they guy that I got it from had wired the resistor on it so that the computer thinks that there is no knocking. well its been almost a year like this and ever since gas prices went over $3.00 a gallon I have been putting 87 in it. I now hear a knocking and I dont think its my VTCs.

Im going to replace the wiring harness but what I want to know is should I replace the knock sensor also. I was told that the knock sensor was new when I got the car but something happened with the harness and he hadnt gotten around to replacing it. so since its knocking should I get a new knock sensor or should I just put the new wiring harness on it and leave the sensor alone?

sorry for the thread jack.

 

if you're doing the harness, you'd be an absolute moron not to do the sensor

 

if the knock is all the time ie idle and wot, low and high load it has nothing to do with the KS. I would diagnose the knock instead of throwing money at somthing that isnt going to fix the knock and proboly didnt cause the knock in the 1st place it could be vtcs, lifters or worn bearings

 

Simply: Read Nissan statement.

- I dont drive an ambulance, thus my O2 utilization is NOT emergency. This comparison is unvalid.
- KS is not used ever by my VG. But as KS dies, makes VG intermittent poor gas guzzler and takes suddendly pwr out. Not thats an serious emergency I have bypAssed...
- Engines have diff req how/where/bywhom they are used. This KS makes VG, VE etcetc engine global. Even for saharan blondies...

I will allow new KS installation in my max, if:
- smbdy pays, and
- ALSO adds ign timing indicator on my dash. Always displays if KS goin to kill me...

 

If you are going to trick your KS into telling the ECU everything is perfect you might as well trick it and tell it you have the perfect air fuel ratio aswell.

Hell just put a carb on it and call it a day








If your KS is honestly pulling enough timing to adversely effect your driveability then you need to spend some quality time and money with your car and figure out what the problem is and fix it.

let me guess, your base timing is at 25*?

 

- Greenpee minded ppl dont allow that.
- I am no match to O2/nissan, want to keep that 32mpg at 60mph hiway

No track around, want to keep license, thus 0-60 [0-100kmh]:
with asthmatic KS, 10s or more
current: definitely under 7½s

Last summer, unlawful tst, 15½s

 

A faulty KS can be a very bad thing. After I insalled my turbo, the KS would pull timing for no reason and at random times. Once that happened my EGT's would hit 1500 deg under part throttle. That's the reason I bypassed mine, and I have had no problems since. I know this isn't really on the arguing topic, but just thought I'd throw that out there. Ultimately, as long as the person knows what they are doing and knows the possible consequences, bypassing the KS is a-ok in my opinion.

 

yeah.

My whole point is what Matt (subs) was saying. I just don't want bypassing a KS to become a run of the mill thing where people do not understand every aspect of what they are doing. There are alot of guys on here who just lurk and still follow our lead so we just have to be careful with some stuff.

All of our cars are different, it's just something we have to keep in mind. I never had a problem when I had mine bypassed and I ran it on 87oct at 20* with about as much of a load as you can put on these engines and didn't hear any pinging. Davebonds car had 92 oct in it and as soon as we hit 17* it would ping lightly on partial throttle and heavily on WOT.

 

Can someone give a link to how to bypass it?

 

NO! .

 

Why not just place it somewhere else like finding a decent spot elsewhere on the block or head??? It may be a little less sensitive but not GONE.

 

I believe it's several hours labor to remove.