Louie Max

I wanted to know what would be the best oxygen sensors for a 97 nissan maxima. I changed the 2 before ones no less than a yr ago with Bosch oxygen sensors and yesterday driving on the highway the CEL came on and read that oxygen sensor 2, bank 1 was malfunctioning. Should i just change all of them or just change the one that is reading bad? What are your opinions on Bosch o2 sensors also,
on a side note i have a warpspeed y pipe and a magnaflow high flow cat.. thanks

willard00

iTrader: (1)

im assuming you are talking about the universal bosch? if so, ive had one for about 4-5 months with no problems. ide say check to make sure none of the splices came undone. and if youre going to replace it...just replace the ones youre getting codes for. some people say to 'play it safe' and replace them all, but IMO its a waste of money. ones bad, replace one not all & save money. if you get a code down the road for another one, replace that one. its not like changing them is that hard anyway.

oh yea, and the best ones are probably the ones from the stealership.

Louie Max

denso would be the oem o2 sensor right?

the_3d_man

iTrader: (1)

No. Denso is not the OEM, Bosch is. It really doesn't matter though. They send the same signal. Just get the universal one and wire it yourself (it's three wires...) save 50 bucks. Ebay has them.

willard00

iTrader: (1)

so does advanced and autozone...so why wait for them to be shipped?

Louie Max

If i am correct, this car has two o2 sensors before the cat and one after,
which one would be BANK 1 sensor 2? ...thanks

andrei3333

i definitely agree 100% with what willard00 is saying. I guarantee you there will be one person who will make a post on this very thread telling u how u r gona get bad mileage with 02's that are in there cause they are old and clogged and dont pass the right voltage to the ecu slightly out of spec.

This is madness. Only replace when u get a code and save the money. the 02 sensors have a voltage range so even if it may be slightly lower or higher it is still within spec. and you will never notice any minute differences in mileage

BunGhoLeo

FYI, 9 times out of 10 when you get an o2 code it's not because the o2 is bad, it's because the reading the o2 is getting from your exhaust is out of the normal operating range. Pull your plugs for that bank and read them. Your plugs are the first step in diagnosing a running engine problem. Could be cylinder specific, or overall.

If it's just the right bank "rear" o2, it could be an injector, coil, or in rare case's a bad plug. If your engine is running fine, but has a rough idle i would lean towards a cloged injector.

The after cat o2 will tell you when your cat is bad. Well, actually the computer takes readings from the pre-cat o2's and compares it to the post cat o2 to determine if the cat is bad.

willard00

iTrader: (1)

uhh no? if the problem were coils, plugs, or injector you would get a misfire code. not an o2 code. i could see why you might think that, cause the engine is running rich so the exhaust would have raw fuel in it. but the crankshaft position sensor senses a skip(misfire), so the ecu will determine that a cylinder is not firing and thats why its rich. therefore giving a misfire code, not o2.

edit- as for the location of the O2: http://www.nissanhelp.com/Ownership/...TIFICATION.htm

Louie Max

So Bank 1 sensor 2 would be the sensor before the cat?
thanks for all your help..

BunGhoLeo

No, a bad injector, coil, or plug are not always completly dead, Those conditions won't always throw a misfire code, but they will normally cause a lean/rich condition which is an o2 code. I suspect the injector cause that's normally the culpruit.

willard00

iTrader: (1)

true, but this is more like a 1 out of 10 chance rather than 9 out of 10.

BunGhoLeo

No, it's 9 out of 10. Most injecters will clog up before they go out, due to cheap, or dirty, or low octane fuel. Your milage will vary on how long you can get away with it. If the nozel on the injector isn't eroded away some injector cleaning will usally help it.

the_3d_man

iTrader: (1)

since when did low octane mean cheap and dirty. There's nothing cleaner about higher octane fuel. It just has heavier hydrocarbons that require more energy to combust. And no... if it is giving you an O2 sensor code... it's probably the O2 sensor. Trying to guess some other cause is dumb. I;m not against pulling the plugs in bank one to inspect them... but don't just assume that it's an injector...

BunGhoLeo

[QUOTE=the_3d_man]since when did low octane mean cheap and dirty. There's nothing cleaner about higher octane fuel.[/quote

Umm, yes there is...

Finnaly someone is getting close...

I'll learn you guys yet.
HINT: http://forums.maxima.org/showthread.php?t=104931 and search for oxygen sensor

KRRZ350

iTrader: (29)

ummmm, actually you're completely wrong about everything, especially the fuel quality thing. Anyways, there are seperate o2 codes for when rich/lean conditions are detected, so everything you're arguing is completely false.

Sensor 2 is the skinny one behind the cat.

BunGhoLeo

No, not everything, but i was a bit misleading about the o2 sensor codes. I figured someone would catch on sooner.

Higher octane fuel is cleaner in the sence of burning, and immersion residue. You can search on the web about the refineing process of all types of fuel. You can also get ahold of he MSDS sheet for all grades of fuel and compare those as well.

Louie Max

So sensor 2 bank 1 would be the firewall side sensor correct?
again thanks again for all your help =]

andrei3333

The MSDS sheet does not contain any information regarding the cleanliness of fuel. The purpose of the Materials Safety Data Sheet is to provide preventative measures, hazardous ingredients, first aid instructions.

You will not find anything about how "clean" 87 is compared to 91, sorry but wrong again.

why would u want to be vague on purpose and try and see if anyone will catch on? dont forget there are some new people on this site that only need the cold hard facts and not tricks or misconceptions.

KRRZ350

iTrader: (29)

that's sensor 1, sensor 2 is the one after the cat, their is only one sensor 2 on your '97, so disregard the bank 1

willard00

iTrader: (1)

a code gives you a GENERAL area of what is wrong. therefore, any sensor that goes bad gives you a code for that certain sensor(hence an area). 9 out of 10 times, replacing the sensor will fix the problem. but there is a small chance it will do something like what you are suggesting and be a different problem related to the same area of the code.

but yes, 93 does burn cleaner than 87. i agree with you there. i think people are taking the 'clean' too literally. clean just means it burns more efficiently. not that if u run 93 the life of the car then take the engine apart the injectors and everything will be cleaner than if u ran 87.

edit- oh and i ment to say that if its a bank 1 sensor 2 O2 code, that has absolutely NOTHING to do with bank 1 of the engine. it only tells you which O2 is the one setting off the code.

KRRZ350

iTrader: (29)

93 does not 'burn more efficiently'. The higher the octane number, the less heat it can produce, it ignites at a higher temperature and contains less energy. Running the lowest possible octane that won't detonate will always provide more power and efficiency. In the case of our maxima's, 87 would detonate, but the knock sensor will detect that the car has 87 and retard the ignition timing. On a car designed and tuned to be run on 87 running 93 WILL cause less power, there is less available btu's the higher the octane, it is a very common misconception that running 93 will cause your car to perform better, in the case of the maxima with compression levels and ignition timing designed for 93 yes, in most everything else, no. 93 is no 'cleaner' than '87

andrei3333

Our maximas will not necesarilly knock on 87, the KS detects KNOCK but not the octane u r running, u can get away runing 87 with a functioning KS if it does not detect knock and throw a code.

gatorsteeler

feed your engine steak, not ramen noodles

c'mon peeps...follow the guidelines to your car or wait for your over-anxious sensors to detect your cheapness...your call. keep your vacuum lines clean, egr, iacv, anything else clogged-CLEAN! if your manual says use 91 octane, do it retard. ive had my car for 2 weeks now and have an EGR and o2 code (never heard of that happening lol)...i learned in the first hour of looking through these forums that these cars emissions and ignition systems are sub-par...why would you want to give it any more reason to grace your dash board with that beautiful CEL? these cars have individual systems i.e emissions systems, fuel etc. if you screw up one thing (or let it get screwed by neglect) in that system, it will throw a code in the area of that system and not always EXACTLY what the code says. not fun to trial and error but u gotta do what u gotta do.

maximafrenzy

iTrader: (11)

I would have to disagree with you on this note, my family owns gas stations from non-branded to Shell, out of all of them Shell vp power is the cleanest most well mixed gas amongst the majors here in Cleveland. (BP, Marathon, Sunoco, etc.) Your paying more for the chemical blending and filtering process, its all 87 oct. from the refineries, then takin to labs and mixed. 91+ is filtered in a much better process than 87, anything in between in some cases is mixed half 87 oct. and half 91 oct. which is what they call plus or 89 oct.