bigorangexj

I did a search, and front what I see people run a few different brand o2 sensors, but I have been advised by some people including my mechanic that dealership o2 sensors are highly recommended. Is it really necessary to dish out that kind of $$? I need both downstream sensors, and hope this is why I am getting a best of 275 miles/tank (85% hwy). I see Bosch at my local Advance Auto for about $95-$125. Should this be decent enough? I definitely drive pretty "aggressively" everyday and highway average is 80-90 (2.5k-3k rpm). Seem to be getting about 18 mpg, but I expected at least 22. Always use 93 oct. Thanks

Rods03Max619

iTrader: (5)

If your doing 80 to 90 on the freeway there's your answer on the gas....but if you need new 02 sensors OEMs are like the same about 115 at 1stnissanparts.com....

foodmanry

iTrader: (15)

I love how everyone quotes their mileage by the tank. This is a terrible indication of gas consumption unless you physically run the tank dry in between every fill-up. It is best to provide an MPG...gosh, I know, so difficult to calculate!

You also have the NGK O2 sensors as well. I have them and they seem to be ok, but my mileage has gone down every year. They aren't throwing an SES code yet, but I'll be changing them soon and going to OEM. They have over 150,000 miles on them so time to change.

I don't know if you will see a vast difference between Bosch, NGK, and OEM. But I would say if they are all about the same price you might as well go with OEM.

bigorangexj

Thanks for the link. Regarding the speed. I bought the car in Mass (I live in CT) and used like 3/4 tank driving home and I kept it under 75 for the most part driving home and that tank I got 17.8 mpg, so I don't think it can be directly related to average speed. I know higher rpms will mean lesser MPG, but my old '96 3.0 Max got at least 25 mpg's doing the same or slightly less hwy speeds, but 80 was about 3k rpm. New 3.5 Max, 80 mph seems to be about 2.5k rpm. Is it just the larger displacement that would cause more gas consumption. Still seems like it shouldn't be 7 mpg less than old Max. Planning on a tune up too (fuel filter, plugs, etc.), but maybe combined with new o2 sensors I'll see an increase.

PadawanKnight

iTrader: (1)

Just stick with OEM. IIRC, the Bosch do not come pre-wired to attach to the harness. You'll have to splice the wires. The OEM sensor comes with the correct end piece already attached. I would imagine that NGK would be a "generic" sensor as well, but I could be wrong.

foodmanry

iTrader: (15)

NGK O2 sensors are plug and play, no splicing necessary.

mahanddeem

Denso....Downstream O2 sensors don't do anything other than cat converters function check

nelledge

iTrader: (6)

Your memory may be a little rusty or you bought the incorrect part numbers. The Bosch OEM replacements require no splicing. Plug and play. Exact same length, same wire shield down to the color, same exact connector, and even has the push clips on the wire to hold it in the stock location. Everything is the same as the one I replaced sans Nissan emblem.

Rods03Max619

iTrader: (5)

How many miles is on your car anyway? Stock rims or aftermarket?

auveeb

iTrader: (3)

Can someone in here help me in this thread: http://forums.maxima.org/5th-generat...-post-cat.html since theyre loosely related? Thanks a lot

Shift_A32B

iTrader: (14)

I agree with nelledge, you probably bought the wrong part number . I bought a Bosch o2 sensor for my max and there was no splicing involved; just plug and play.

cabernet

I bought 4 of the Bosch O2 sensors from Advance Auto. I split it into several orders and used promo code BIG35 which takes $35 off of $85. Great if you have a local Advance Auto store. You can order online, use the code, and pick up in store. If you have to have it shipped then your order needs to be more than $110 with the promo code to get free shipping.

bigorangexj

Thanks for the code if it works. My car has 85k miles with 17" aftermarket wheels (on car when I purchased). Can the o2 sensors be done myself with minimal tools/experience or do I need to reset something to get the SES light off?

dhundley79

I just bought a used 00 Maxima with 175k miles. I took it in for a check up and on the way in my CEL came on. Took it to Advance Auto - shows bank 1 sensor 2.

was told I need to get oem sensors (both downstream) and then have the ecu reflashed.

Question I have is can I simply buy the ones from Advance, pull the battery terminals and make the ecu forget its previous programming and go on with my bad self? I dont have $650 that the dealer wants to do it.

thanks for any help

sontakke

Listen to this guy! Downstream O2 sensor i.e. BnS2 (where n=bank number:- 1 firewall, 2 radiator) only checks if your pre-cats are working or not.

For mileage degradation you have to look at the upstream sensors and MAF etc along with transmission slippage brake dragging etc.

- Vikas

dhundley79

havent had a true mileage pull yet. havent gone through a tank of gas yet. 180 miles at half a tank. does sound like it runs rich though. my friend that is a nissan mechanic is who told me to replace the sensors but, i think he saw the TSB for the sensors and left it there. Rear calipers also need replacing. i can reset the CEL and it will stay off for a bit. reset it last night and drove 30 miles all highway and it did not come back on yet.

I really want to keep the car but I cant afford to make this many repairs all at once. Im kinda let down that my "mechanic friend" missed these. but who knows, could have been perfect and a week later these could have started anyways because it is a "12 year old car"

sontakke

If you are looking for help do this
1) Get the actual code number or better buy a cheap scanner; they are getting ridiculously cheap these days
2) Go fill the tank right now and compute your actual miles per gallon by dividing miles traveled by the gallons filled. You do NOT have to wait until your tank is empty. You are getting approximately 20mpg which is not bad depending upon your driving style.
3) Check your wheels after you park your car from an extended drive. If any one of them is lot hotter than the other three, you have dragging caliper or may be just a frozen pin. A good mechanic will check the slider pin before condemning the caliper.
4) Get the code and then we can speculate on it further.

Or you can start throwing parts at or give carte blache to mechanic/dealer to replace the parts. It is your choice whether you want to do this systematically assuming you have the inclination and the ability.

dhundley79

Hey I really appreciate the reply. I just had it scanned and this time it came up as p0430. and mileage was 21-22mpg 90% hwy miles. I would much rather do it myself to save the money and to learn a little bit more. I've done spark plugs and brake pads and valve cover gaskets. I'm open for all any suggestions

Amave

why not get a DMOV and test your sensors?


locate the signal wire ( iirc its the middle white one one our cars ) your volts should change in real time up and down from .1 volts up to 1.0 volts rapidly. if at any time you see the volts stay at one spot, the sensor is bad. Do this after the car is warm ( operating temp. )

Both oxygen sensors upstream ( closest to the exhaust manifold ) are the ones responsible for fuel economy and efficiency.


I just changed my oxygen sensor by the radiator since i was putting in gas every 2.5 days ( i only let it get to 1/2 tank before i get gas. ) and after the sensor change i go about 4 days before putting in gas.

Thats not very scientific but i can see my fuel economy go up.

I tested my sensor and the volts were staying at .1 v for about 2 seconds to long, they should be changing instantly .


Hope this helps and if you need any more help let me know

papo99

iTrader: (33)

i just replaced all my o2 sensors with bosch plug n play no splice. but i searched ebay and amazon and ended up paying about 250 for all 4

dhundley79

Wheels didn't really feel hotter than one another. Calipers have lots of rust. One side has already been changed. MPG showed 21-22. That's 90% hwy miles.

sontakke

OK; P0430 code is for catalytic converter efficiency low. Ignore it unless your state does emission. In 99% of the cases, it means you need new pre-cat, preferably OEM one. That costs quite a lot. If you google, there are few ways to get rid of the P0430 code. Search under my name here and you will find the way to fix it.

Try this next time you are on the highway and have full tank. Drive as if you have donut spare tire on the car i.e. drive very gently and stay under the speed limit 55-65. Take a raw egg and strap it to the gas pedal (and to the brake pedal) No seriously, just drive like a grandma for few days and then do the same mileage measurement. You will get a huge jump. Is your car manual or automatic? Do you have slippage? That would rob the mileage and would be very bad.

22 mpg is not too bad. To see if this is too bad, you will need to get a scanner capable of getting live data. Once again, these days you can pick one up cheaper than a tank of gas!
If you have Android platform, you can pick up a Bluetootch dongle for under $20 (I did!) OR you can buy a standalone scanner under $100. They are really cheap. I have multiple and keep at least one in each of my car. Using scanner live data and little bit of knowledge, you will know if you need the primary O2 sensors if they are lazy. You can monitor the MAF signal to see if you need it to be replaced.

Since you have done brakes and valve cover gaskets etc on other vehicles, you have capability to easily do most of the maintenance on this vehicle. Obtain factory service manual (google it). Since you do not know much about the history of this vehicle, assume you may have to replace all the consumable parts e.g. plugs, filters, fluids, MAF sensor, O2 sensors etc but you can do this intelligently rather than throwing parts. Spark plugs are very easy on 2000 Maxima. Replace or make sure you are running the OEM (i.e. NGK Laser platinum/irridium) Accept no substitute. If you find Bosch in there, throw them away and get the NGK (about $7 a piece).

Forget P0430 code! That is not causing you any mileage or performance problems. Definitely do NOT replace the rear O2 sensor to fix that because it will NOT be fixed if you do that. Put my name and P0420 or P0430 in the search box and you will find more than you would ever want to know about those two codes!

- Vikas

dhundley79

I live in a county that does not require emissions, so i will look through here for fixes. The car seems to be running fine, plenty of power and at idle you dont hear it running really.

It is an automatic, and I will attempt at driving like a grandma, I grew up in Dallas (TX) - hard to drive anything slow. I dont ever even fell the transmission shift.
I just ordered one this morning for my android phone, guy that cuts my hair has one and says it works great.

Plugs will be the next thing done, oil was changed 2days after i bought it. I have a long list because there is some rust on the car. Rotors will be next, will check to see if they are still in spec and may have them turned or just simply replaced. If I do replace the 02 sensors should i go factory and have them do the ECU reflash or will the Denso work just fine ( I see them range from 60-135) any difference?


Doing this now. Do you have messenger of any type that I could chat with you on?

You are completely awesome and thank you for all the help

sontakke

You are welcome! I have similar 2000 GXE 5-speed but now my son drives it. So I am familiar with this vehicle. I am a poser though i.e. I am an internet mechanic :-) I have all the tools including three impact wrenches and five scanners but I have even better mechanic and I have him do all the work for me! Internet has made all the resources available to people like us and if one has the inclination and the tools, majority of the diagnostic works cane be done by an individual before the car has to see a mechanic. I have not even changed my own oil in decades now. So you have to take my advise with a grain of salt.

I am an engineer and interested in cars so I learn as much as I can. Even my mechanic respects me and does what I tell him to do as he knows that I know what I am talking about. I always obtain (buy/find) factory service manual and Haynes manual for all my vehicle and study them. When I take my vehicle in for service, I put on the gloves and start using my own tools when the vehicle is on the lift.

I check this forum quite often, so fire away.

Don't cut the rotors. If they are pulsating now, just replace them. When you cut them, you are making them thinner which means they will start pulsating even sooner. Buy medium quality rotors rather than spending money on cutting yours.

For O2 sensors, stay with OEM just like the spark plugs. I believe O2 sensors are either Denso or NGK(NTK?). If you need them (scanner live data would tell us lot of about their condition) buy them from Rockauto or internet Nissan dealers. No reflash is needed. Give your car few good dosage of fuel system cleaner such as Techron Concentrate Plus, or Redline or Gumout Regane. You should be able to get at least one from the list at your local Walmart or autoparts store.

By the way, your mechanic is confused. O2 sensor replacement does not need ECM re-calibration. He is thinking about MAF sensor replacement. However, for our car, the re-calibration is not really necessary for MAF replacement even though Nissan suggests it. There was a technical service bulletin which re-flashed ECM so that P0420/P0420 code occurrences would be reduced but your car is too old for that reflashing. I had done it on my car and reflashing only delayed the P0420 by couple thousand miles. Fortunately, I was still within 8/80K, so I got one new pre-cat gratis. Guess what, the other one went at 100K miles. Hint "O2 sensor extender"; get the stainless one.

Why is your mechanic telling you to replace caliper? What are the symptoms? Is rear parking brake working? Is is sticking? Is the parking brake cable rusted? If you work on the rear brakes, get the tool to screw the caliper in. You might be able to rent it or buy it from HF but don't try a cheap cube thingy; that will not work :-(

Is the axle boot torn? Is axle making noises? Then yes, you need to replace them. But make sure it is axle which is making the noise and not the rusted brake backing plate rubbing against the rotor.

If you want to save the money, you will have to start asking questions to the mechanic or find another one who you feel comfortable. You want somebody who will work with you and not against you.

Amave

BTW the oxygen sensor i bought from NGK was part number 24619, it's the sensor closest to the exhaust manifold and both of the sensors are the same ( radiator and firewall ) .

After i replaced the one that was laxy my MPG's went up to around 27 mpg , from about 23.


I drive to work 83 miles round trip having to stop for gas every 2 days when it got half tank, after i tested my oxygen sensors i found the one by the radiator not switching quickly ( like it should ) and i replaced it and my MPG's went up .


I plan on putting up a video on how to test it

sontakke

That is the way to do it i.e. test it and if it is not switching quickly then only replace them. Also look at the underhood sticker. Almost all of the Maxima's sold in USA had California emission. Rockauto shows NTK 24527 for Left pre-cat and 24619 for right pre-cat. If one of them is weak, the chances are other will not be too far behind and then you might change them both. Denso part numbers are 2343109 and 2343111 and they look like the factory replacement with the correct length and connector. I will not put anything else i.e. no universal or no Bosch etc.

Scanner will tell you lot if you can watch the voltage and/or fuel trim and bank to bank variation.

dhundley79

thank you again. Bought a scanner off amazon. hooks up to the car and shows me RPMs and all the goodies. shows me what the 02 sensors are doing. but the SES is on and torque comes back that there is no codes in the ECU memory. I can hit clear codes and the ses light goes off. can a bad precat make the car sound loud? i feel like anytime im about 60mph it gets louder and louder. Im looking for a new mechanic, although my current one is a friend I need a second opinion. I feel as if I bought a big pile of junk right now. Anyone intersted in a lovely 00 maxima gle. :P

sontakke

aaaaaaaaaaarrrrrrrrgggggggggg

So the scanner is not giving you the code even though the CEL is staring at you, right? You checked both stored and pending codes, right? What about the freeze frame data? It is called something else but it is there on the main options. That would make me mad too. Ask this question on the Torque forum, I heard the developer is very responsive. Otherwise, you might have to find another scanner. Buy it from a store which has good return policy e.g. Walmart. You need to know if the code is P0430/P0420 or P1320

With the scanner, you need to set it up so that you are only watching one or two parameters. Set it to watch primary O2 sensor voltages in graph format and have somebody else drive the car. You want the voltage to be constantly switching between high and low (0.1 through 0.9).


- Vikas