Knock sensor or feul filter???

Hey heres' a ??. I just had the exhaust done on my X and all was good until today, when I noticed I was down on power. It feels like maybe a knock sensor went or maybe the fuel filter is shot. It feels like I have a "dead spot" around 1500-3000 rpm range and the the S/C tries to kick in and it doesn't feel as strong as it should. It has 60000 miles on it and have never changed the plugs and/or the fuel filter. Help me out on this one!! Thanks

Go to auto zone and have the codes pulled. Then tell us what you find.

OK...ran daignostic test and found 1 code for the knock sensor..code is p0328 high circuit input. Could this be because of the new exhaust?? It didn't say the the sensor is bad, could it possibly be that I have too much airflow and if so do they make a better knock sensor or should I get a cold air intake to even up the flow coming into the motor??

Oh and also, is it easy to replace the sensor if I have to??

Most likely a bad knock sensor. The nissan engine will not turn on the SES light with just a knock sensor out.

I will see if I can find a writeup on the knock sensor replacement.

You're the best Alpine!! Also..do you think that if I put a cold air intake on it would it even the air flow out??
Thanks

I cant seem to find a good write up on the knock sensor replacement.

In terms of a cold air intake it will improve the performance a hair, or even if you change out to a K&N drop in filter.

You must remove the supercharger and manifold to replace the knock sensor. If Nissan does it you're looking at $750-$1000 P&L to do it. It's a real PITA! Mine just went out too. With a supercharged engine you gotta replace the sensor. The power loss you'e feeling is when the knock sensor goes out it retards the timing and bypasses the blower. The sensor is located on the left bank between cylinders 2 and 4.

A P0328 is a bad knock sensor code

Well then...hi-ho-hi-ho its off to Nissan I go...thank god I have an extended warranty!! Already called to see if it was covered and YES my friends it is!!! Otherwise it was going on the auction block!!LOL Thanks to all that helped me out!!

Do you always feel the power drop? Or does it go away when you shut off the engine and restart it? That's what mine does.

BigE, the power drop occurs after each trip of the sensor. The KS is a one reset sensor. Turn the truck off, it resets. Turn it on and go a few miles and boom, it trips. Then it retards timing and bypasses the blower and gets REALLY bad mileage. The only fix is to replace it. My only question is, could something like a bearing noise from the nose gear on the blower trip the sensor? I've noticed this on mine. I just don't know what comes first. The nose gear noise or sensor trip. If the gear is noisy all the time I could see it tripping the sensor or if the sensor trips and bypass occurs, is the bypass causing the noise?

Why isn't there a recall on this?!?!?

Nissan

Exactly!

Strange thing this morning. Got all the way to work, 18 miles, and the KS never tripped. I had full boost all the way... :rolleyes:

I just don't get it.

Same thing happens to me...when the motor goes through the first heat cycle is runs great, then it starts to happen intermittently, I don't get it.So it's going to the dealer to be looked at.

Hello, I've had this same issue for about 1 year now. I have an 02 with 58,000 on it. I took it in under warranty and dealership replaced the supercharger(parts $1800)and no charge because of powertrain warr. Anyways, tech asked me if I ran anything under 91 octane in it because it would trip the bypass. I always run 93 and had belts changed at 30,000. Nonetheless, I still have the issue. Seems to occur once it has warmed up and between 1800 to 3800 rpms.It's a really bad lag.

We should all print out a letter with how many miles we have, the problem, what's been replaced, the year of our X's, name and address and mail them all together in one big envelope.

I'm glad at least others are having the problem so that we can hopefully find the solution a little easier. I just don't think I can take it in and drop $750 to $1000 right now. A recall would be a lifesaver. The lag is a safety issue if you try to pass or merge in traffic.

a. Parts wear out

b. Sensors wear out, Knock sensor, O2 Sensors, MAF sensor

c. If you buy any vehicle expecting it to last forever and not have to fix something.... get a damn bus pass.

d. The knock sensor wont be recalled it is a maintenance issue, so fix your shit.

Damn Kev.....I detect a little haste in your last post. Most of us can fix our "SHIT" but when you start fixing the same thing over and over again, you start to wonder if its a reliability issue with it.Am I wrong?? :rolleyes:

So, two knock sensors "wearing out" before I get to 40,000 miles is normal? Thanks for the input, now go roll around in your Nissan stock, smartass. :p

I just hate to hear everyone say "OMG my parts broke (wore out) Nissan better do a recall so I dont have to pay".

Knock Sensor every 3 yrs or so seems to be the norm for Nissans. The KS will not throw a code on its own and I bet I can walk up to any nissan that is more than 3 years old and get a voltage code with a code reader on about 40-50% of them.

Nissan Stock HA!!!

Well I did manage to get about 70,000 miles out of my second sensor. I guess I should be thankful. Access to this sensor should have been engineered better for the supercharged engines. But yes Kevin. I will fix my shit. I do think Nissan should do a recall for the supercharged engine to do a refit of the sensor somewhere else on the engine. I also know that would never happen.
What really sucks is that it's not something you can ignore or let go, unless you don't mind having a truck with about 100hp and get 7mpg.

I didn't even get 10,000 miles out of my 2nd sensor. Never had this problem or anything like it with any other vehicle that I have owned. Luckily, I only get the power drop (which isn't always there) and not the big drop in mileage.

Hey Alpine...I just got back from the Nissan dealer and they said that yes their is a knock sensor code but all systems passed and they cleared the code and when I drove it home the same shit happened..loss of power and ran real shitty. In your one post you said sensors wear out...since it started doing it again,do you think the knock sensor is "going bad"? Because I will go back and insist they replace it. Let me know what you think.

I am willing to bet it is a bad sensor. It tripped the code in the computer again on the way home and when you take it back it will be there again.

Or you'l go back to the dealer and they will tell you that there is no problem and that the irregular power drop is caused by the larger than stock tires you have....even though the tires are on there all the time and the problem isn't there all the time.

Alpine and BigE,checkout the post question in the performace part of the forum I put in and see what u think, otherwise I might have to take off the 2 1/2" piping and go to the stock 2 1/4" to get some backpressure back. Thanks..Andy

Well after some thought...I'm insisting that the sensor be replaced...I can't come up with a logical reason that the 2 1/2" pipes would make the sensor retard the timing thus not allowing any supercharger assistance to the motor. Wish me luck.

Good luck! I'm going back to the dealer lat ethis month or early September and I'm not taking "There's nothing wrong, no change in acceleration at all." or "It's because you put bigger tires, thats why there's a drop in boost." as excuses. I'm printing this out and taking it with me! LINK

Good idea BigE...I'll print this also,but i don't think they will hand me excuses, the X is the 4th vehicle from the same dealer so I'll pretty much tell them to replace the sensor and it'll be done.

I have a appointment with the dealer that told me my oversize tires (32's) are the cause of my boost drop. When I called the guy on the phone asked me, "This vehicle is modified, correct?" -"Yes but nothing has been done to the engine that would cause a drop in boost." Sounds like I'm in for some more BS. :rolleyes: Any suggestions? Magnuson-Stevenson Act? Better Business Bureau? tell them, "There's nothing wrong? So if I go to the sales depatment and tell them I want to trade this in for a '07 Off Road I'll get full value, right?" Drive my X through front window?

Bige...Does your X lose its power right after the first "heat cycle"? I know mine does so I went and got a 170 degree t-stat and droppin that in and see how it does. Still haveing Nissan put the new sensor in too. A cooler motor produces more HP so I know it won't hurt.Oh and about driving it through the window....get some pics, I would love to see that! LOL

Oh and also the dealer said that your tires are the reason for the boost drop....thats bullshit anyway due to the fact that you went down 2" in your wheel size (from stock 17" to 15") then it should theoretically even everything out right?? Also definitely print out this forum and bring it with you, thats a good idea. Andy

My truck obviously doesn't like going to the dealership, the KS hasn't acted up since I called to amek the appointment yesterday. I never noticed if it does it when the engine warms up or not, I know it does a lot more and comes a lot faster in the winter months. The tires...I have 32's, that isn't much bigger than the stock tires for a SC model anyways. :rolleyes:

I'm not sure it would be a good idea bringing this to the dealership with me since I was joking around about driving thru the front door of the dealership.

I'm gettin mine done wednesday so I'll let you know how it runs...this better fix it or else it's goin up on EBAY!!LOL

O.K. so I went to the dealer to get the sensor replaced and of course the problem didn't show up, so the mechanic showed me what to look for if the knock sensor was bad. On the back left side of the S/C there is a vacum hose connected to a "bladder" that has an arm on it...when the engine is idleing the arm is halfway open and when full throttle is applied the arm is completely vertical....if the knock sensor sees a problem the arm will be all the way down therefore shutting down the S/C. And of course that didn't happen while I had it there they told me when it happens either bring the truck to them if I can or call them asap and they will change out the sensor.Also they told me that the o2 sensor could be at fault and also if I do change the t-stat to the 170 degree that I have that could also help the "detonation issue" that I'm having.....STAY TUNED THIS IS GETTIN GOOD FOLKS!!!!

Wow, I am really glad I didn't opt for the supercharged engine when I bought my Xterra 4 years ago. I still remember the dealer trying to impress me with the Supercharged model, I just didn't think the extra 30 HP was worth it.

Well so far since my trips to the dealer, the knock sensor hasen't showed up since. I guess its tempermental?? Now it runs like an animal...rips 2nd to 3rd gear upshifts again!!

My first question to the dealer. "If its a knock code and the sensors fine whats causing it? Engine coded are thrown for 2 reasons a bad sensor or a sensor detects a problem that is try to compensate for to not damaged the vehicle." Simple as that. So if there is not problem...I doubt there is, they better change the GD sensor.

Secondly, How would a colder t-stat cause detonation? detonation is caused by too high cylinder preasure or temperature or too much timing. A colder t-stat would help.

BTW how would bigger tires affect boost level?? Thats unbelievable I can see it now "Well sir you tire size changes the gear ratio so that basiclly translates through the entire PT and in turn turns the blower slower" Are they serious?!? Tell them to pull there heads out of there asses and fix your truck and then to go learn more about how different components on a vehicle relate or don't.

Exactly what I said, how can tires which are always on the vehicle affect a problem that isn't always present? They just stared at me...."Get the manager, please." ---He's not available. "Fine, tell him to call me when he feels like it or magically becomes available. Give me my keys." :rolleyes:

Hey Ryan...I took your advice and disconnected the battery for 30 mins and it seems to be running well. Put in a 170 degree t-stat (pain in the ass!!) and will be ordering the cold air intake asap. Thanks again

Andy

Glad I could be of help. Hopefully thats the end of your troubles. I would highly recommend the AEM Brute Force, easy install, looks good fits great, and most importantly it works!

I have a Airaid intake and I've been thinking of going back to stock just to see if sucking in all that hot engine air maybe contributing to the problem.

the airraid didn't come with a heat sheild?? Most of them do.

It did but the insulation strip at the top fell off and even with it, how much heat does it really keep out?

When I put in my K&N drop in filter I first took out the airbox and drilled a couple of holes in it below the filter to get as much air in I possibly could but still would like to drop in a cold air to see if theres a difference.

trust me...do it...it's not like ass kicking back in ur seat power..but its an intake...it's totally worth it.

Guys, Your knock sensor problem will return. Changing the T-stat won't change the conditions of a knock sensor.
If you are running premium gas of at least 91 octane you are doing all you can do. You have got to change the sensor. No other sensor or condition will mimic a knock sensor code and trip the sensor. Just change the sensor. Mine's going in next week. It's easy to tell if you have a bad sensor.
1. if you have a vacuum/boost gauge.It will show a 1-2 lb boost when the sensor is thrown.
2. if you have a scan gauge. It will show p0328 code.
3. sit at a stop light, turn on your A/C and then try to take off at a high rate of speed. it won't happen. It will be like dragging a 1000lb anchor.

I can't wait to use that one at the dealership, "Use a scan gauge, p0328 code will show up." Thanks!

Actually I've used all three situations. I have the boost gauge and see when the sensor trips. 2 lbs of boost. I borrowed a scan gauge and when the sensor trips and see theres no boost I then look at the scan gauge. yep, a p0328 shows up. You can clear it then but it won't reset untill the engine is stopped and restarted. Also, like I said. take off with a tripped sensor with the a/c on. The truck struggles.

The sensor is extremely tempermental. Got all the way into work this morning and the sensor didnt trip.

Same here, mine doesn't act up all the time. It's like it's messing with me.

After talking to several mechanics that have worked on Nissans of all types for years, I was told that the knock sensor gets more and more sensitive as it gets older. And it seems the ones Nissan uses are the worst of the worst.

Great, thank God I got a 7 year/75,000 mile extension. Unless ofcourse the pricks give me the runaround and tell me that it's not the knock sensor or that it's my fault due to modifications again. :rolleyes:

Yeah mine goes in on the 25th to get the sensor changed...after going there 3 times and tellin them the same symptoms mentioned in frontiers post. I finally told them to change it!Period! It's not like they won't get paid for it so whats the big friggen deal. And by the way, it's been running fine but I know it's still there!! Damn government mandates!!!

Are you refering to this [URL=http://www.amazon.com/ScanGauge-Compact-Multifunction-Computer-Customizable/dp/B000AAMY86/ref=pd_bbs_1/105-7441547-5958868?ie=UTF8&s=automotive&qid=1187312887&sr=8-1]LINK[/URL ] or a code reader?

Bige
Thats the one. Just remember, you can reset the code on the fly with the scan gauge, but since the KS is a one reset sensor, it requires the engine be turned off and on to totally reset.

Oh, I thought you were refering to a code reader. I don't need a $150 gizmo to tell me the knock sensor is crap but the dealer sure as hell does. You got me all excited that I'd have some hard/idiot proof evience to show the dealer.

Well shit, I pay off the X and shit starts to happen. My SES light lit up went to AutoZone and Not only did O2 sensors come up bad but so did the PITA KS. I dont guess any one replaced it on there own, and if so is it worth the headache or should I pay some monkey (no offense Allen/mechanics ) to do it?

I heard that if you have a body lift you can reach the wires that go to the knock sensor so that you can relocate the knock sensor to an area where you can change it without paying $1000. F*cking Nissan! I don't understand how some people on here can act like having to replace your knock sensor is regular maintenance. :rolleyes:

Yea man, from what Im seeing its a FAAAAR cry from changing ones oil,flushing rad., brake job and what not. It ranks up there with timing belt change. BTW no body lift here, DAAAAAMN IT.

Sounds liek an excuse to get one! I'm thinking about doing it in the spring.

You have got to be kidding me. No other input/advice on this issue.

There's a lot of posts about this. From what I've heard, it's in the center of the engine and costs about $1000 to have done.

Yea, BigE, Ive read/searched the issue. Has anybody done the fix and if so how involved is it. One post said somthing to the effect that the SC needed to be removed, if so why. As far as the location it does not make sense to me to remove the SC.

I've never done it, I don't intend on trying. I'd rather push it off a cliff than try to do that!
Good luck!

Yea its a real PITA. I guess Ill try and bypass it, are there any ill side effects to that that you know/heard of?

I am having this same problem and have been fighting with Nissan. Their Conumer Affairs Dept. is the worst. I will never buy another Nissan product again after all of this. Woodfield Nissan flat out lied to me also. Went to Autozone, they ran a scan, P0328 of course, took it to Woodfield Nissan in Schaumburg IL and they ran a test, "claimed" there was no code and I found a print out under my hood with P0328 from the dealership 2 days later!! Bastards flat out lied to me and charged me $107.

Might try to fix this myself this weekend. Let me know what you guys find out.

Blower and manifold must be removed to access the KS. You'll need a new set of gaskets for the blower and manifold to put it all back together.

Mine now has the problem of the blower itself is making bad bearing noise. Went to a PSE blower website and found a replacement for $650.00. I called and talked to a rep and they said if i got 100,000 miles out of an eaton blower then I did good. he also asked how often I changed the fluid. I said Nissan didnt have a change interval for it. That lit him up. He said it should be changed every 30,000 miles.
So lets see:
KS replacement $750.00-$1000.00
New blower $650.00

This really sucks!

What?!? Wow, thats ridiculous! I'm surprised no one has come in here to defend Nissan yet. :rolleyes: I jus mailed my last payment out and I have 45,000 miles so I'm not about to trade my X in but it is annoying.

I LOVE my truck. Don't get me wrong, but if you have issues, there should be a good customer service team to take care of you. Nissan is a major co. and they SUCK at customer service.

I also talked to Woodfield Nissan last year about changing the oil in the supercharger and was told I don't need to because it gets lubricated buy a feed from the engine oil???

How do you changed the oil in these Eaton's?

The blower does not get lubed by engine oil. The supercharger is an independent system. There is a small plug on the front of the blower that you would remove, drain what you could and refill. There is a special blower oil/lube. I don't think Nissan looked at the supercharged engine as a long time use engine. How could they if theres no mention of a blower oil change interval.

Just spoke with another dealer and he also said that the supercharger gets lubed from the engine oil. Are you guuys 100% sure it is fully independent and needs oil? That is what my first thought was. I also put in a call to Nissan Corp. again. Last time it took 10 days for a call back.

Let's see how long it takes this time!

I'm going by what PSE told me. I've looked at my blower and cant find an oil line to it.

Im curious what sort of life expectancy Nissan expected out of the SC engine?

After 12 weeks, the knock sensor was replaced by Woodfield Nissan, under warranty so I get the initial $107 back I paid. The truck works fine now. Covered under the 5 year, 60,000 mile emissions warranty (which is different from the extended warranty. ) This has been the biggest PITA ever. Nissan Corp. sux big time.

I wish I could convince my dealership that it is the knock sensor and not the tires! :rolleyes: