98maximaSS

ok guys heres the prob i got the code 05-12 and i checked everywhere and found that it is the rear o2 sensor it came about cause i lost to a 99 5.9 L durango and i checked the codes i need to make sure that its right i know its not 1205 because i had my friend watch the light i need help!!my car has no pull at WOT and in 3rd it wont pull pass 6000 rpm and i want to fix it ASAP thanks alot

Rutnick

rear 02 sensor has nothing to do with driveability of your car. It is more for emissions.

clogged cat or partially clogged cat?

TheMax95

I think I have the same problem with my 96 5speed. I have really bad gas mileage and it just doesn' pull as hard as when I bought the car with 73k miles on it. Now it has 110k. I changed the fuel filter and plugs but it did nothing. I'm hoping it's the o2 sensors cause they are $$
-Paul

joosdawg

iTrader: (9)

i dont think it has anything to do with drivability as rutnick says, if that were true then people with straightpipes installed (i have full straight pipe to muffler no cats) would have little to no acceleration like your stating. i too have the 0512 code but thats because i have no cats and your right its not posted anywhere that i found to tell people thats whats malfuntioning. the rear o2 sensor just detects that the cats arae doing there job nothing to do with drivability but if your not piped then i suggest to replace the o2 sensor clear the codes and see what happens

Broaner

iTrader: (10)

Bullsh!t. Everyone thinks that the rear o2 has nothing to do with performance. Well it doesn't directly relate to performance. When working properly the rear o2 reads between .01 & 1.5 volts. But when its been destroyed it reads zero volts. Believe me its happened twice to me. Both times were cause by the sensor contacting the ground. So you may be thinking to yourself that its no biggy to be reading zero volts. You assume that the ECU realizes that its being faulty and disregaurds the information as it throws the code to let us non-envirionmentaly concerned b@stards know that the cat is busted. Well, the ECU doesn't disregaurd. Infact, it reads the information loud and clear even though there is no time during the sensors life that it would read zero volts 100% of the time.

So, its reading 0 which means that the ECU is being told that the engine is running lean. The system reacts by putting in more fuel. But only to a certain point. To a safe level. It doesn't run so rich that smoke is coming out the exhaust but it runs rich enough to cause you to get 250-300 miles to a tank and lose roughly 10-20 HP/TQ because we all know that a rich combustion chamber isn't making much power. The car will top out at 123 in this situation. Enough said.

Now, it is very easy to check if the sensor has dragged the ground. Simply get on your knees and look. Or you can hook up that OBD-II scanner and see what the d@mn thing is reading.

joosdawg

iTrader: (9)

so what about in my case where i have a straight pipe and throw the code and still get well over 400 miles per tank and seem to only have accelaration issues due to my bad knock sensor? or is it the fact that mine isnt dead yet its mearly getting a s*it exhaust reading due to having no cats?

98maximaSS

allright guys thanks broaner i think i have a handle on it now with the info. do you guys know a cheap place to buy good 02 sensors i went to o2sensor.com and found the downstream o2 sensor for 62.31 or something is that a good price? i dont deal with sensors a whole lot but i would rather do it myself then let the dealership do/gimmie anything so thanks again

Stephen Max

iTrader: (59)

How do you know all this? I ask because the FSM for the 95 model states unequivically that the downstream (rear) oxygen sensor is used to monitor the health of the cat and has no effect on engine performance.

joosdawg

iTrader: (9)

exacly what i thought if it affected performance i wouldnt have a straight pipe

TheMax95

Just to clear things up, how many o2 sensors are on a 96 max? I remember seeing 2 on the ypipe when I installed it but is there another one by the cat?


Also, where can I get o2 sensors the cheapest?
-Paul

joosdawg

iTrader: (9)

yes correct theres 3 total

KnowledgeBorn

iTrader: (2)

Glad theres is a thread about o2 sensors, but my question is just a bit different. I am in the process of replacing all 3 sensors on my '99 SE (92K). I bought the Walker universal sensors from oxygensensors.com and they shipped very fast, I used the Maxima.org discount as well. My mechanic says that I shouldn't use the universal sensors because they are not a direct fitament, he says that even though you do the splicing sometimes universal sensors just fail to work properly and you end us replacing them. Has anyone replaced their sensors with universal types and had any problems? Thanks in advance for any and all responses.....

Broaner

iTrader: (10)

I know this because its happened to me twice now. I just got my sensor in the mail from OxygenSensors.com yesterday. I popped that bad boy on and I saw what I had been missing in the Max for nearly two months. I was unable to replace it earlier because I was away being a counsler at a camp. The first time the sensor was destroyed by a high spot in the middle of the road. The second it was clobbered by a stray rock. Each time this happened to me the Max became very sluggish off the line and top end. You won't notice a decrease in MPG on a road trip but you will on spirited city driving. On the way home from camp I got just over 400 miles on a tank which is a slight decrease from normal but in the city I was getting 250-300. As I said earlier a Max with a faulty rear o2 will top out at around 123 depending on conditions.


joosdawg, if you would use proper punctuation I would be able to tell if you were agreeing with me or not. As is, I'm interpreting that you don't agree with me and stated, "if it affected performance i wouldnt have a straight pipe." By this statement it is clear to me that you did not read the entirity of my post. I clearly stated that it indirectly effects performance only when its broken and reading zero.

KnowledgeBorn, send those POS universals back and get OEM. You'll thank me later. Your mechanic is correct. Think about it though. How much are you saving? $22.04 per front o2 and the the rear universal is more expensive. There is no reason to use a universal. If you can't spend $40 extra you need a new hobby. Also, its a real PITA to splice that ****. You turn a five minute job into an hour x 3 very quickly.

4DRSpeed

iTrader: (22)

Glad to see a topic on O2 Sensors. I rolled 156,000 2 weeks ago and about 3 miles afterwards my engine light came on. It came back with 0702 and 0703 codes.

Three-way catalyst left & right bank!

I was told this has to do with the front 2 O2 sensors on the ypipe. I have a Budget Ypipe, and I believe maybe that the mechanic screwed up putting it on. I believe he got frustrated getting the stock one off and just threw the new one on.

I have my ypipe wrapped, which is suppose to decrease the bees in the can noise, but in fact its clearly loud enough to be embarrassed when revved.

I was told that the codes tell me I either have an AIR LEAK, EXHAUST LEAK, or BOTH O2 SENSORS are gone.

How can I check for an air leak, or exhaust leaks? And if the O2 sensors are bad, can that cause a bees in the can sound still even though my ypipe is wrapped?

I am getting bad city mileage as well. When using conservative throttle I only get about 250-300 miles like broaner states.

killcrap

iTrader: (3)

u should be getting around 400-430 miles per tank. of course granny driving. your o2 sensors affect your milage and performace but not a WOT(wide open throttle) it cause some lag when tring to accelerate from stop.

DAVE Sz

iTrader: (2)

400-430 a tank? Ha, you're dreaming. You can get that on the highway but "granny" driving doesn't really go together with the highway. If you get that much in the city, you're one lucky dude.

To check for exhaust leaks take out a spark plug and pour in a teaspoon of ATF in the hole. You'll get lots of smoke so you'll be able to tell where it's leaking. Oh, and you'll clean your cylinder while you're at it.

Broaner

iTrader: (10)

killcrap, please explain why top speed is effected if o2's aren't used to alter the fuel map on WOT. Fuel maps on consistant under ideal conditions but the fuel load changes when one of the sensors is reading zero all the time.

4DRSpeed, start by replacing the front ones. The rear code is often tripped due to being fooled into running extremely rich or lean. Hook up an OBD-II reader and then you'll be able to tell which is giving you trouble.

DAVE Sz

iTrader: (2)

Stephen Max

iTrader: (59)

Please cite the reference.

Stephen Max

iTrader: (59)

There is documentation to show that the ecu does not use O2 sensor information under WOT conditions. That is what is referred to as open loop operation (which begins at a throttle position less than wide open, actually). Fuel metering is controlled by maf sensor information and throttle position only during open loop operation, and the ecu controls injector duty cycle using preprogrammed look-up tables.

That at least is what happens for a normally operating VQ. I would agree that perhaps an O2 sensor that is completely out (like your situation) would result in a different operating mode, e.g. a limp home mode. I guess that would explain your lowered top speed.

98maximaSS

well guys i can tell you that my preformace has been severly hurt and that my o2 sensor isnt competley dead its has what i like to call "moments of unexplained operation" which is to say that when to car is cold it runs like a beast but after 10 or 15 mins driving its back to its sluggish and almost civic like responsiveness and im going to change the o2 sensor and i will get back with you guys on the subject i cant stand it and oh by the way broaner is 100% right about not going over 123 even with over drive off it just sits at 6000 rpm and wont go any higher cant redline in 3rd like i used to to get to 135 or higher it just plain sucks i dont know what eles to say but as far as it not effecting preformance i can attest to the fact that it does make you lose lowend from a stop and there is nothing at speeds above 55-60

Peace

4DRSpeed

iTrader: (22)

What O2 Sensor brand do you guys recommend? I'm thinking about getting the Denso brand. Also what is the discount on Oxygensensors.com website for us?

Just thought I would share that I get a slight hesitation above 2K RPM sometimes. Would this have to do more with the O2 sensors than a possible exhaust leak? I know it's not my knock sensor I just replaced that puppy last month.

Also my car can be sluggish at times as well. I will be replacing these two very soon. I would still like to know though. I have my ypipe wrapped if O2 sensors went bad would that cause a loud raspiness even when wrapped?

Broaner

iTrader: (10)

Any of the brands found on oxygensensors are fine. Boosch seems to have developed a good reputation but all work fine.

I don't think the hesitation has much to do w/ o2 sensors. Keep in mind I say, "Don't think." So, I don't really know.

Bad o2's wouldn't create a raspy noise unless somehow the metal got chopped up some how but I can't see that happening. The raspy noise your hearing most likely is not cause by the flex section either. I had the same noises that everyone does but it was cause by the gasket between the collector and the cat. The gasket that the y-pipe companies give you is to small. The gasket material sticks out into the exhaust stream and therefore creates the raspy noise as the piece vibrates or flutters back and forth. Unbolt that part trim the gasket and I'll bet your problem is gone.

cardana24

iTrader: (81)

bosch is the stock O2 sensor in a fourth gen

DAVE Sz

iTrader: (2)

Believe it or not, if the stock GROUNDING ring and wire are removed from the CAT bolt, they CAN cause the rear O2 to go bad. FSM states that one reason for rear 02 to go bad is a loose ground wire.

ThurzNite

iTrader: (13)

reference: fsm. wanna verify? pm me.
Jae

DAVE Sz

iTrader: (2)

??? Clarify how? The FSM(factory service manual) states that the CAT bolt ground can cause the rear O2 to go bad.