Hi
First / Supposing I have 3 faulty O2 sensors ... and I don't have anything else bad in my max.........what will happen if I just leave them as they are and not fixing them ? will this have any impact on my car overall or the engine specifically ?

Second / just imagin that the question was about the knock sensor ...will this damage anything if not replaced ?

Thanks

 

i am a noob here and know that this has been discussed hundreds of times. try using the search link at the top and read the noob guide.

to answer your question, your car will run like crap - your gas mileage will go down drastically and you will feel a significant power loss. also, you will fail your emission test.

 

As was said, you need to search.

Crap MPG, CEL.

No, the KS will not 'damage' anything if not replaced.

 

You're noooby and you talk like a moderator ...what will you do if your posts exceed 1000 ? ban me from here ?

 

As if 1000 posts makes you a moderator?

 

ok about the MPG ...what about the performance ? will it be affected ?

 

Part throttle, likely. WOT? No.

 

Balkan is right. With bad O2 sensors the ecu will use rich fuel maps, which will cause loss of power and terrible fuel economy.

For a bad knock sensor, the ecu will pull timing, resulting in loss of power.

Start by replacing the upstream o2 sensors if you're on a budget. The ecu looks for a differential reading between the up and down streams.

 

let me sum this down for ya. if you dont have an o2 sensor, the world will come to an end and thousands max's all around the world will explode. ok fo real this time.... basically all that will happen is that u will fail emissions, wont pass inspection, and your engine check light will turn on. its a good idea to have one but i dont believe it will cause any harm. im a noobie too...so help me out and give me feed back plz

 

it will not cause any harm but it will hurt performance and fuel economy, as stated above.

yes, i am a "noooby". i am as much of a part of this forum as you are.

 

Can you please gimme a link for how to change front oxygen sensors with photos ?

 

The oygen sensors are going to have to be replaced because the car Is

going to have poor MPG and the car is going to preform poorly. The car is

going to burn more fuel The KS is a biggy because the car is going to suffer

in accelerations and drivability because of the ks and the loss of 20 HP. If

you think this Is BS just SEARCH.........

 

Search, it's not that hard.

 

If your rear O2 sensors (Post-Catalytic Converter) are bad, your fuel economy and performance will not be affected.

If your front O2 sensors (Pre-Catalytic Converter) are bad, your fuel economy and perfroamnce will suffer.

What Codes are you getting?

 

Spartuss put it well. My rear O2 sensor(s) are bad and I'm getting 26-30 mpg and she feels fast as ever.

 

No you're not...

 

go get a haynes manual, they have nice pretty pictures and will explain what you need. If you have to ask where to get one and cannot search, we cannot help you. We are here only to help you after you have helped yourself. The search button can be tricky, just make sure that you click on most relevant near the bottom

 

just search for the fsm for your year max, gives you all the info you need, the most youll need to change them out is wd40 and some sockets special for o2 sensors. i rented some from the zone for free, just do it from the bottom. . .(thats wat she said) lol jk
i couldnt help myself
but yea, those sensors cant be that much

 

Perhaps I'd get 30-38 mph if I did?

 

How do you figure?

 

sensors can cost anywhere from $40-$130 depending which one it is and what kind you get. There are oem ones where you don't have to splice the wires, or ones that you have to splice the wires yourself. You can even use an open ended wrench, or if you feel more comfortable, get an 02 socket wrench. Either way, they shouldn't be too hard to get off. Use some pb blaster if need be and let it soak for a while. It is best to get the pipe semi-warm to hot so its easier to get the 02 sensor off

he's got jedi powers?

 

im glad somone posted this im having the same problem and ive noticed the fuel decreasing and the accel as well thanks guys

 

i just picked this sensor up from usautoparts.com for my 95, its an ntk which is an oem direct fit sensor. bank 1 sensor 2, 78.25 shipped to my door in 2 days. front sensor is about the same as well as the rear o2 ( i believe only the 95/96's had the cat sensor )

 

You can't mix the two phrases. "It feels fast as hell" And "I get 30mpg" In the same sentence.

 

They're not mutually exclusive. Just doesn't mean that he's getting 30 MPG while going WOT.

Look at the Corvette...feels (is) fast as hell, gets close to 30MPG.

 

Yaaa...but...
A 4th gen maxima = 5,000$
A c5/c6 vette = 20k$ +

I'd hope for 20-40 grand I'd get power and decent gas.

 

Oxygen sensors communicate necessary fuel increase/decrease (fuel trim) to the ECU. So an old sensor will constantly read too rich and will attempt to lean the mixture at all times. To combat this, the driver will usually push the throttle harder, ironically burning more fuel. Long term problems are loss of power, poor fuel economy, check engine light (limp home mode), and possible overheating since a lean mixture burns hotter than a richer mixture.

*This is in reference to the front/main oxygen sensor, the rear one only measures catalytic converter efficiency and will only act up if you have removed your cat... I recommend fooling the damn thing rather than ever purchasing an expensive replacement. (Can be done a variety of ways, research it)

A crappy Knock Sensor will constantly be pulling back your spark timing, causing incomplete combustion. Long term problems will be loss of power, poor fuel economy, misfires, check engine light (limp home mode), and possible damage to the catalytic converter(s) from raw fuel burning up in the substrate.

A bad Knock Sensor will also hasten the malfunction of an oxygen sensor, so do the KS first, then the O2.

 

You won't get misfiring or a CEL from a bad KS. It's also very unlikely that it retards the timing to the point of incomplete combustion (well, more so than normal, anyway).

Remember, Nissan designed it as a fail safe system; if it's damaged, the ECU will attempt to keep conditions reasonably safe, and it's extremely unlikely they would have designed the system such that it could possibly cause converter damage.

 

HAHAHA that is funny