# 2000 Nissan Maxima, PLEASE HELP!!!!!! P0430



## Maxima1987 (Jul 22, 2007)

I have a 2000 Nissan Maxima and it runs and drives great except for in the morning. The car has one code and it is the p0430, catalyst efficiency bank 2. In the morning the idle is really high and it runs good, but when you put it in drive it will die out sometimes, but it will start right back up. Also, until it warms up it has a wierd sound coming from somewhere on the right side or underneath the car, it sounds like a faint rattiling sound, almost like a bad cat or something??? Also, it just sounds real dry and it sounds like a pulley is grinding at times. These could be numerous problems or just one, but when it warms up it runs really good and it is really quiet and smooth. ALSO, when sitting at a light with it idling even when it is warm, there is like a bubbley sound coming from the right side of the car and you can here it inside, but you can not here it when you get it out, and if ou mce the wheel around it will stop. When you get out of the car you can kind of here it on the right side but you can feel it in the body, it is like puttering, but if you push down on the fender or anything on that side of the car for that matter it stops. Suspension seems fine. Now that was just the engine, when I make a slow sharp turn when pulling out somewhere it sometimes makes a really loud clunk sound once and thats it. It sounds like a piece of metal breaking loose. This car is spooky, please help!!!!!!!


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## brianw (Feb 25, 2004)

Either means the rear cylinder bank precat is failing

You sure you don't have a leak somewhere? Leave the car running, pop the hood, then listen around using a rubber hose or something maybe an inch in diameter (an old garden hose works great too) to see where the noise is coming from...


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## Maxima1987 (Jul 22, 2007)

brianw said:


> Either means the rear cylinder bank precat is failing
> 
> You sure you don't have a leak somewhere? Leave the car running, pop the hood, then listen around using a rubber hose or something maybe an inch in diameter (an old garden hose works great too) to see where the noise is coming from...


I do not think there is, do you mean like a vacuum leak? I just took it to nissan and they could not find anything wrong at normal operating temp, but they are going to keep it over night and then test again. All he found was the rear oxygen sensor was acting funny he said, also found out my coolant fan was unhooked and when he hooked it back up it started to shake. Anyway, Nissan said his best guess was the idle air control valve sticking. I am so confused because all of the noises and everything. Thanks for posting.


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## brianw (Feb 25, 2004)

Strut mount on the passenger side front could need replacing, that would explain the clunk.

Faint rattle...? Precat or main cat could be broken but it's hard to say. I would replace the rear bank o2 sensor and see if that helps before you start thinking about catalytic convertors.

The "real dry"... what the hell does tat mean? If it sounds like a pulley grinding your idle pulley (tensioner pulley) for the accessory belt could be failing.

Bubbly sound means nothing to me-- get someone else to stand outside and listen for it. You gotta do some diagnostic work yourself here, the rest of us troubleshooting over the internet can't do everything for you.


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## Maxima1987 (Jul 22, 2007)

brianw said:


> Strut mount on the passenger side front could need replacing, that would explain the clunk.
> 
> Faint rattle...? Precat or main cat could be broken but it's hard to say. I would replace the rear bank o2 sensor and see if that helps before you start thinking about catalytic convertors.
> 
> ...


I have done dignostics myself, but that is why I am here because I have no idea what it is. The dry sound I hear just means it sounds rough, like its running without oil it just has this sound and feel in the moring and the best way to describe it is "dry". Thanks for the help.


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## brianw (Feb 25, 2004)

Record it and post it so we can tell. That doesn't describe very much, unfortunately. Most cameraphones these days DO record audio too, although it's pretty crappy, so find someone with a digital camera that does cheesy little movies and use that...

My opinion so far has already been provided based on the available info, that's about the best I can do for you at the moment.


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## Maxima1987 (Jul 22, 2007)

brianw said:


> Record it and post it so we can tell. That doesn't describe very much, unfortunately. Most cameraphones these days DO record audio too, although it's pretty crappy, so find someone with a digital camera that does cheesy little movies and use that...
> 
> My opinion so far has already been provided based on the available info, that's about the best I can do for you at the moment.


I dont here any vacuum leaks and Nissan did not find any either. I got the computer reprogrammed and the car has a smoother acceleration, but the noise is still there. Just imagine what a car sounds like with a muffler system installed and then take that sound and rap it up in a towel so that it is muffled and put it in my engine compartment. Nissan said that my drive belt was in horrible shape and I looked at it and it is all craked and real shiny on the back, could that put a bind on my pulleys? I do not have a recorder or I would post the sound. Anyway, my plan of attack is to replace the oxygen sensor and then I am going to take the throttle body off and clean it and clean the Idle Air Control valve and then put a new gasket on it. I have cleaned the throttle body plate before but it was still on the car. When I looked at it, it had a really dark black ring right around where the plate closed at. Also, could a bad power steering belt make a faint poping sound some out of the engine compartment by putting a strain on to me power steering pump. I know a lot about cars and what the parts do but I am just lost completely on this car. I work on it everyday. Thanks!


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## brianw (Feb 25, 2004)

Definitely replace the accessory belt. While you're in there have them check the idler pulley (aka tensioner pulley) and see if it needs to be replaced or not.

Power steering may be driven directly off the main accessory belt in a 5th gen, I can't remember. Replace it anyway. Cleaning the TB is cheap and easy to do so you might as well do it while you're cleaning the IAC motor.


> a car sounds like with a muffler system installed and then take that sound and rap it up in a towel so that it is muffled and put it in my engine compartment.


that doesn't tell me a damned thing, sorry.  (I've heard aftermarket exhausts on more different than vehicles than you can count.... tiny 250cc bikes, 600cc bikes, liter bikes, I-3's, I-4,'s flat-4's, flat-6's, I-6's, V6's, V8's, V12's, W-12's, etc. etc.... I've heard Evos that sound almost like stock despite a 3" exhaust and I've heard Evos that resonate off the damned walls a hundred feet away, etc. so the noise you're trying to describe with that has too many different possible qualities in my head  )


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## Maxima1987 (Jul 22, 2007)

brianw said:


> Definitely replace the accessory belt. While you're in there have them check the idler pulley (aka tensioner pulley) and see if it needs to be replaced or not.
> 
> Power steering may be driven directly off the main accessory belt in a 5th gen, I can't remember. Replace it anyway. Cleaning the TB is cheap and easy to do so you might as well do it while you're cleaning the IAC motor.
> that doesn't tell me a damned thing, sorry.  (I've heard aftermarket exhausts on more different than vehicles than you can count.... tiny 250cc bikes, 600cc bikes, liter bikes, I-3's, I-4,'s flat-4's, flat-6's, I-6's, V6's, V8's, V12's, W-12's, etc. etc.... I've heard Evos that sound almost like stock despite a 3" exhaust and I've heard Evos that resonate off the damned walls a hundred feet away, etc. so the noise you're trying to describe with that has too many different possible qualities in my head  )



Well all I can tell you is that it is making that kind of sound. I am not sure what model the sound is...lol, but the main thing I am wondering is could it be the throttle body making a sound like that. Also, the oxygen sensor that is bad is where the sound is coming from because it is right under my feet. I am thinking that there might be a hole next to it, and I am thinking that could be what through my oxygen sensor off. I am about to spend a bunch of money though and do allt his work, I will post everything when I am done. Oh and remember the suspension sound I was talking about, well it ended up being the brand new lower control arm I just had put on the car, the bushings are already bad after 8 mos. Thanks for your help!
God Bless!


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## brianw (Feb 25, 2004)

Swap out the lower control arm bushings with Energy Suspension units, they should be more durable.

The o2 sensors in the exhaust manifolds screw into cast iron manifolds so I doubt there's a leak there, but a leak in the joints to the y-pipe could make sense.

Can you feel any leaks from the TB? If not, then that's probably not the source of the leak.


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## Maxima1987 (Jul 22, 2007)

brianw said:


> Swap out the lower control arm bushings with Energy Suspension units, they should be more durable.
> 
> The o2 sensors in the exhaust manifolds screw into cast iron manifolds so I doubt there's a leak there, but a leak in the joints to the y-pipe could make sense.
> 
> Can you feel any leaks from the TB? If not, then that's probably not the source of the leak.



Could you explain more on the energy suspension units, i have never heard of them. Also, I have been searching for a long time for a rear oxygen sensor with california emissions, does it matter what kind or where it is supposed to be located as long as it is a rear oxygen sensor, because I can not find the exact part. The nissan part number is 226a0-4L710. Do you know where I could find this exact part. Also, what should I do if I get one of the sensors and the cable is not long enough? Thanks!


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## brianw (Feb 25, 2004)

Welcome to Energy Suspension! ... have a looky. Most major online aftermarket parts places sell them.

As far as the sensor goes, any Nissan dealer parts department should be able to order it for you. The cable will be the right length, unless you got the wrong part, so don't worry about it.  The rear o2 sensor should be the same, CA emissions only means there's an additional o2 sensor up front.


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