# Problem with the knock sensor, please help.



## jkucukov (Nov 29, 2005)

Ok, just recently about two weeks ago my 2.4L engine started to throwing out a code 304 which is the fault knock. I have taken the sensor off and tested it it reads 576 k-ohms which are the apropriate specs. I reseted the code and two weeks later the check engine light was on again for the same 304 code? I've checked all the wiring and the sensor again and everything seems fine, what to do I ask my self?


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## 2000SE (Oct 28, 2002)

How are you scanning it? 

http://www.troublecodes.net/Nissan/95ams96-00.shtml


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## Asleep (Jan 19, 2003)

you can get a knock sensor code for almost nothing it seems. but dont worry too much about it. if youre not experiencing bad mileage or poor driveability, youre probably looking at a code that was stored because knock was felt or it occurred. check your timing and remove the knock sensor and clean it and the mounting spot carefully and reinstall it. sometimes you get a code simply because the harness or the sensor itself is dirty or oil soaked.


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## jkucukov (Nov 29, 2005)

2000SE said:


> How are you scanning it?
> 
> http://www.troublecodes.net/Nissan/95ams96-00.shtml


I got a Hayens altima book and using OBD2 scaner to check for the code.
On the website you gave me (http://www.troublecodes.net/Nissan/95ams96-00.shtml) its saying that the P304 code is for the misfire in the 4th cylinder, my hayens altima book says othervise, who to belive???????
what to do next, Could the cylinder # 4 misfire because lack of fuel? because i also got another code just now P171 which stands for the fuel system being too lean.


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## 2000SE (Oct 28, 2002)

*Haynes is best used to start the fireplace*

What year? Cali or Fed emissions? Download your factory service manual. 
http://phatg20.net/modules.php?name=Downloads&d_op=viewdownload&cid=69

The combination of the two codes(misfire and lean) scream to a vacuum leak.
My vacuum leak was the intake manifold gasket. Its a common issue.

Good luck.


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## Asleep (Jan 19, 2003)

2000SE said:


> What year? Cali or Fed emissions? Download your factory service manual.
> http://phatg20.net/modules.php?name=Downloads&d_op=viewdownload&cid=69
> 
> The combination of the two codes(misfire and lean) scream to a vacuum leak.
> ...


lol, haha.


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## jkucukov (Nov 29, 2005)

2000SE said:


> What year? Cali or Fed emissions? Download your factory service manual.
> http://phatg20.net/modules.php?name=Downloads&d_op=viewdownload&cid=69
> 
> The combination of the two codes(misfire and lean) scream to a vacuum leak.
> ...


how do you supose to view that file? I downloded the file for the 2001 nissan altima and it cant find a program to open with. 
I dont think its a gasket leak (car has only 40k on the engine) I might check for that but also check the spark plugs, distributor and cables, maby timing too just to be safe.


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## 2000SE (Oct 28, 2002)

Download it into a folder. Then unzip it with winrar or any program that can unzip RAR files. Then, use adobe acrobat reader(another download) to open it..

winrar:
http://www.download.com/WinRAR/3000-2250_4-10446177.html?tag=lst-0-8
adobe:
http://www.adobe.com/products/acrobat/readstep2.html

I went through the timing/plugs/wires/thermostat/caps/rotor/tons of FI cleaner......only to replace the intake gasket. 

Yours is a 2001. Is it an automatic? does it have Cali emissions? 

Your vehicle "might" be covered under the powertrain/emissions warranty which will cover the intake gasket. I'd run straight to the dealer before wasting money on parts that should last longer.


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## jkucukov (Nov 29, 2005)

2000SE said:


> Download it into a folder. Then unzip it with winrar or any program that can unzip RAR files. Then, use adobe acrobat reader(another download) to open it..
> 
> winrar:
> http://www.download.com/WinRAR/3000-2250_4-10446177.html?tag=lst-0-8
> ...


My car is an automatic. I am in utah, how do you know if its california emissions?


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## 2000SE (Oct 28, 2002)

Dealer can tell you, which you need to visit anyway to see if your car is still under the powertrain warranty.


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## jkucukov (Nov 29, 2005)

2000SE said:


> Dealer can tell you, which you need to visit anyway to see if your car is still under the powertrain warranty.


even if I am the second owner on it.


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## BORNGEARHEAD (Apr 30, 2002)

I've also seen a bad mass air flow meter and bad fuel pump for the P0171 code. But the intake gasket is a pretty good bet, especially on cyl.4. Try this. Take a can of carb cleaner, gum solve, etc, and spray it along where the intake manifold bolts to the cyl. head. If you notice the idle speed up or smooth out, def. intake manifold gasket leaking. If no change, do a fuel pressure test to see that the fuel pump is in spec.

As far as the dealer, as long as the vehicle is under 5yrs and 60k miles, it is under the powertrain warranty. It doesn't matter if there have been 10 owners.

Also, you can tell if the vehicle is Federal or california emissions by looking at the white label that is on the inside of the hood. Look at the last sentence of the label.


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## jkucukov (Nov 29, 2005)

BORNGEARHEAD said:


> I've also seen a bad mass air flow meter and bad fuel pump for the P0171 code. But the intake gasket is a pretty good bet, especially on cyl.4. Try this. Take a can of carb cleaner, gum solve, etc, and spray it along where the intake manifold bolts to the cyl. head. If you notice the idle speed up or smooth out, def. intake manifold gasket leaking. If no change, do a fuel pressure test to see that the fuel pump is in spec.
> 
> As far as the dealer, as long as the vehicle is under 5yrs and 60k miles, it is under the powertrain warranty. It doesn't matter if there have been 10 owners.
> 
> Also, you can tell if the vehicle is Federal or california emissions by looking at the white label that is on the inside of the hood. Look at the last sentence of the label.


Borngearhead you really know your stuff, thanx for the tip.
What the car does it realy has a hard time idling for couple of seconds and then it smooths back out, it keeps oscillating like that during the whole time the car is at idle. I thaught the injectors are dirty. 
Why did you say that generaly No. 4 cylinder has a vacum leak on the intake manifold, is that just a common problem on No. 4 or could it be on anny other one. As far as the dealershipp goes do i just take the car in and dont worry about the cost. I can only pray that the delershipp mechanics will be handeling my car with care.


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## BORNGEARHEAD (Apr 30, 2002)

That totally sounds like an intake manifold gasket leak. It idles funny but seems to drive down the road fine, correct? 

The cyl. 4 thing is because 4 out of 5 times, the intake gasket leaks at the cyl. 4 intake runner. I'm not sure why that is. 

For the dealer, make an appointment to go in. When you go in, ask them UP FRONT if this is going to cost you anything and you want to know if your vehicle is still under powertrain warranty or not. If they tell you it is going to cost you something, you have the right to say "no thank you" and leave. If you have less than 60k miles on the car and it is less than 5 years since the "in service date" of the vehicle, that intake manifold gasket will be covered under warranty and should not cost you ANYTHING. The "in service date" is the day the vehicle was bought new, not the production date it was made, so even if the vehicle was made, say, June 2001, that vehicle may have sat on the lot and not sold until, say, Feb 2002. Does that make sense?

If your vehicle is out of warranty, that job won't be real cheap. Parts will be intake gasket and coolant. The rest will be labor. Don't quote me but I believe they are getting 3-4hrs. for labor to do it.


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## gfriedman (Oct 12, 2005)

jkucukov ,

PLEASE look at the emission label thats on the underside of the hood like borngearhead said. Toward the bottom see if it says "conforms to California emissions regulations" OR on the driver door pillar look at the label for the TRANSAXLE code and see if the last 3 letters are -UVA.

If so the gasket is covered to 7 years 70K under emission warranty. You should have no problem getting this fixed even under the drivetrain warranty but PLEASE let us know if you have the california car.

Thanks very much!!!


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## jkucukov (Nov 29, 2005)

gfriedman said:


> jkucukov ,
> 
> PLEASE look at the emission label thats on the underside of the hood like borngearhead said. Toward the bottom see if it says "conforms to California emissions regulations" OR on the driver door pillar look at the label for the TRANSAXLE code and see if the last 3 letters are -UVA.
> 
> ...


"Its not a california model" Already confirmed. The car has 40000 miles on it and its a 2001 altima. Wold the dealer shipp have the car in the computer under its vin to see wheather its coverd or not?


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## BORNGEARHEAD (Apr 30, 2002)

jkucukov said:


> "Its not a california model" Already confirmed. The car has 40000 miles on it and its a 2001 altima. Wold the dealer shipp have the car in the computer under its vin to see wheather its coverd or not?


Yes they will.


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## newburghsux (Nov 24, 2006)

I'm having the same problem with my 2000 gxe. Actually, I just ran the code on it and the misfire on the #4 cylinder is what came up. I wonder if it's even worth changing the spark plugs/wires. Should I just assume that it's an intake manifold gasket leak? BTW, there's 138,000k on it so i'm not really about to drop $650 on that repair anytime soon.


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## gfriedman (Oct 12, 2005)

newburghsux said:


> I'm having the same problem with my 2000 gxe. Actually, I just ran the code on it and the misfire on the #4 cylinder is what came up. I wonder if it's even worth changing the spark plugs/wires. Should I just assume that it's an intake manifold gasket leak? BTW, there's 138,000k on it so i'm not really about to drop $650 on that repair anytime soon.



Yeah you got hit with the gasket problem. But actually you've been luckier than most as the gasket usually craps out much sooner than 138k miles. If you don't want to do the repair yourself to save the bucks then I'd reset the computer and sell it quick before the leak gets worse and the engine starts stalling out. Give the headache to some other sucker....


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## jkucukov (Nov 29, 2005)

I guess I was one of those succers who happend to buy a 2001 altima with 38000 miles on it before the gasket craped out. I did however decided to take the work on and do it my self. OMG, Im a sort of a "your avg. back yard mechanic" and worked on few cars, this car was a nightmare in removing the intake manifold. I still remember there is one screw that I had to leave behind because it was impossible to place it back in because of the space issue. Yea, took me 8 hours to do this thing. 

I'd say identify exactly where the leak is then go buy some high temp gasket sealent and dump a crap load on and arround the runner where the crack is.


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## gfriedman (Oct 12, 2005)

jkucukov said:


> I'd say identify exactly where the leak is then go buy some high temp gasket sealent and dump a crap load on and arround the runner where the crack is.



The odds of that working are slim though if you want to try it'll only cost you a tube of sealant. First of all it's hard to locate EXACTLY where the crack is. Second, even if you could locate it chances are it'll be in a spot that you cannot reach with your tube of sealant.
Good luck....


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## LONDONDERRY (May 19, 2004)

gfriedman said:


> Yeah you got hit with the gasket problem. But actually you've been luckier than most as the gasket usually craps out much sooner than 138k miles. If you don't want to do the repair yourself to save the bucks then I'd reset the computer and sell it quick before the leak gets worse and the engine starts stalling out. Give the headache to some other sucker....


Not a good idea
If your going to sell the car, privately you'll have to disclose the problem(s) to the new buyer. If you hide intake gasket leak from the new owner, and she/he discovers it within a few days you might be forced to refund the money or pay for the repair. Check your state consumer protection laws.


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