what happens if i don't replace KS?
 

The CEL came on this morning on the way to school. I pulled the codes like 10 minutes ago and got the KS code. It's balls cold in MN right now. So I wanted to wait until it warms up a bit. Is this a really dumb thing to do?

Tyler

It doesn't matter whether the car is cold or warm, a code is a code. A faulty KS retards the timing to prevent detonation, resulting in a decrease of MPG and throttle response. I would get it changed if I were you and next time :google: :newbie:

I think that he was asking if it were a big deal if he changed it now or later. It really doesn't make a difference when you change it, you will just notice a decrease in performance and MPGs.

And FYI, if your SES light is on, you have another problem than just the knock sensor.

horrible gas mileage.

this is the truth.


a dead knock sensor WILL NOT CAUSE THE CEL TO TURN ON. there is something else wrong with your car, probably more serious than the knock sensor. i would get it checked asap.


and to answer your question, driving around with a dead knock sensor is not the end of the world. you will not do any extra damage to your car.
the only things that will happen are a) worse gas mileage and b) worse performance. thats it.

ghost code, didnt notice a difference at all when i changed mine.....:ghost:

just poor gas mileage.
Its-20f tonight, I need to replace my water pump(it's leaking bad) but its too cooold!!

Bad knock sensor does make your car pretty slow when i replaced mine it felt like i picked up 15-20hp more then from any mod i did lol. My CEL was on and i had several problems including the KS, TPS, malfunctioning o2 sensor (only got that one once) and a missfire (only got that one once too. The odd thing was that when i bought the car it didnt have a CEL on and i drove it 30 minutes home from the dealer then after a week of driving around the problems started showing up :rolleyes:

THE HONEST TRUTH...........
 

HONESTLY......... RUN 89 or 91-93 Octane in your Maxima.

RESET the Dam ECU.

KEEP RUNNING 89 -93 OCTANE. Maxima isnt made for cheap rice.

THE CODE WILL NEVER COME BACK.TRY IT.
Not sure if its the FIX, but the code wont come back....

Nothing will happen except the lost of power and poor gas mileage. Drove mine like that for a couple hundred miles until I realized my CEL wasn't lighting on (dead bulb). Changed it and discovered why the car felt sluggish and weak. Now it drives like it should.

Don't think it was faulty at all. If you tighten it too much you will cause it to not be as accurate as it should be. Not tight enough and it wont do you any good as well.

That's what happens with KS going bad. It pretty much takes everything else down with it. Only way to really fix it is to change the KS and reset the ECU. Put some nice 93 gas (Did that ever since I changed mine) and feel the power!! You'll also notice all your other codes disappear ;)

Complete nonsense. :smash:

Update: 2 more codes so in total 43 34 126

(I'm taking my car in to the mechanic in the morning, but for fun guess whats wrong)

Knock sensor
Throttle postion sensor
Throttle Position Sensor (Automatic Transmission)

All of which say that a usually high voltage causes code. My car is running over 14.5 volts now due to the cold and was running almost 15 volts when the CEL light came on. I have a voltage meter on the battery at all times because of my stereo so I know this for a fact.

I reset the CEL and turned on the car, its idling rough, no CEL light and theres oil at the top of the dip stick. Also i have some grey soot landing on the snow by the exhuast.

Side notes: I have a budget Y pipe and 2.5 custom piping with a catalytic converter stock on the car. It's about 0 F here and was -5 on the morning when the light came on


Any guesses?

Agreed! That is retarded mate. :(

To the OP: The KS will not give a cel, so the TPS is likely your problem. It's not that bad a job to replace it, but it can be tricky gettig the correct position so you get the right Ohms readings you need. PM me if you need the part, I have one I'll sell you cheap and walk you through setting it up. The carbon (black exahust) is due to carbon build up in the intake. It goes into the cylinder when the valve opens and comes out the exahust. This will cause poor idle and poor running as well. The KS will not cause you any 'noticable' problems. Some may want to argue this, but mine is bad, been replaced, is bad again, and doesn't act any different. So I'm not doing it again. lol Not worth it IMHO. Car runs great, no problems. :thumbsup:

Anyhow ... that's my input. Cheers!

Got the car back from the mechanic... DRUM ROLL!!!!

It was the fuel pressure sensor, which makes a lot of sense.

Tyler

how much?

i had the same problem a few days ago.. check engine went on and codes read o2 and knock sensor! i changed the o2 yesterday then went out and noticed the check engine light turned off.. BUTTT just to be safe i replaced the KS along with the exhaust manifold gasket and valve gasket today and reset the codes and even gave it a tune up! i advice for you to do the same to help you in the long run..

if ur arnd the 100k mark and u have a KS code most likey in the next few thousand miles the common Oxygen sensor code will come up soon. maxima;s r known for the knock sensor and O2 sensor to be faulty arnd 100k miles.

270 for the repair, mainly labor he had to mess around with it for a while to figure out what it was. I plan on doing the KS in the spring as its too cold now... BTW I'm at 147k or so.

Could always bypass the KS with a 470k resistor .... heheheheeh The evil things the Stickyz hold! LOL

Update: got super cold again this morning (-10 F) problem is back. Im getting knock and/or fuel combustion in the exhuast manifold. I got some octane booster to see if it helps as I run non-Oxy gas thats 91 normally, don't know what they do to it for winter blending... I will update tomorrow after I get to work.

Car still idles rough, but seemed okay after the 20 mile drive to work, as in it wasn't rough while driving around in the complex. So we know it's not knocking. I'm still getting exhaust ignition, and unburned fuel.

I think it's the cold, I'm going to park it in the garage tonight and see if that helps. Also I think I need to change the oil too, so I'll do that. This suxs hard...

FWIW: I've had the knock sensor code for at least a year, drive at least 12k miles a year and consistently get 22 city/27 highway (I drive Austin-Houston all the time, check my mileage at every fill-up, results are consistent). I also only use 93 octane. I have a new knock sensor and harness ready to put in when I replace valve cover gasket so it will be interesting to see if this changes anything.


UPDATE: has been a year, mileage didn't change... I find this somewhat odd since you would think the KS code would cause some sort of rich "safety mode" but since I got good mileage before/after I'm not complaining. Also, search ebay for 22060-30P00 and you can get a non-OEM sensor for $20 ($60 for OEM on ebay, dealer is $150+)

It's not COMPLETE nonsense. Running 87 on a warm summer day will trip a KS code. knock will trip a ks code. The fsm is wrong, and this guy is right, only in some peoples circumstances though, but the majority of the time it is due to a cracked, melted, or otherwise failed sensor.

But doesn't it always work that way?

now that I think about it... thats f**ked up. Why wouldn't a bad KS trip the cel?? Nissan wanted us riding around with a boggy gas drinking car and not even know it?!

Maybe one day the engineers had a bad day or whatever and programmed the ecu and were thinking... "screws these guys. you know what, if your kS goes bad you'll never know suckas!!"

I bet in 98 there were plenty of 4th gens running around with bad KS and people didnt even know.. soo much gas wasted and they didnt even know.



:rotz:

/morning random rant

when changing the ks, be carefull removing the connector. its tricky and fragile and it costs 27 dollars at the stealership.

It's because of the way the oversimplified knock-retard on our cars works. If it caused a check engine light people would be getting CEL's after running 87 under the right conditions.

The engineers probably realized 99% of the public would run 87 and the dealerships didn't want to be burdened with KS CELs while the cars were under warranty :p

You're right! They would have lost alot of time/money changing knock sensors. I bet there was a service bulletin saying not to replace them too.

I am at 103k on my 99 SE and had an O2 code and the Knock Sensor Code. I replaced the O2 sensor to get past my inspecton, and the CEL has not come back on. I just replaced the Knock Sensor yesterday and wonder how long I need to drive it before I should check to see if the KS code is still gone?

Thanks

By the way, I have the California Emissions 99 and replaced the KS without removing the uppper and lower intakes.....it was hard to get to, but I am hoping it was worth the effort.

I wouldn't think Nissan would send out a TSB to not replace the KS. If people knew it was bad (which ... how can you tell w/o hooking up to an OBDii scanner?) they would have had to replace it (under warranty). TSB's are basicly a PSA (public service announcement) from the manufacture to allert techs / dealers / people in general of known problems and fixes. You will not find a TSB w/o a 'fix'. Just a heads up. ;)


If you had read, the KS is a ghost code - will not throw a SES light on it's own. With the Oxy sensor bad, yea - then you hook up to the scanner and find the o2 sens and ghost code KS. IIRC, you need to drive ~50 miles or so for it to figure it out on it's own. Best thing to do is to disconnect the bat terminals (both) and then tape / zip tie them together (off the bat!) so the ends touch for 20 mins or so. This will clear the memory and alllow the ECU to 'relearn' as you drive after you hook it back up. Saves you from having to drive xxx ammount of miles before it works like it's supposed to.

It got cold again here in MN like -20's F. I got a gas card from x-mas, i filled it up with oxy gas and not the non-oxy i normally get. And the problem went away.

Weird.