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Car problem..O2 sensor and bad mileage

Discussion in 'The Lounge' started by loco-gringo, Feb 12, 2010.

  1. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Here's the gig...02 Xterra with 115000 miles.

    Check engine had me replace knock sensors and O2 sensor about 400 miles ago. Had valve covers and a water leak fixed at this time. Since getting it, about 120 miles in P1163 code pops again. Put another O2 sensor in and about 300 miles, we got it again. They checked everything yesterday again and can't see anything, but it continues to trigger the code. There are no recalls on it. Shop suggests that Nissan flash the ECM, but there are no shops that will try it without an update. My fuel mileage has gone to like 12 mpg since this started. The only possible thing that the shop can come up with is hairline cracks in the exhaust manifold or an issue with the fuel control.

    Any ideas from the site wrenches??? I'm not stoked about spending more jack since I dropped $1200 a few weeks ago.

    Even less enthused about the local Nissan shop since they took 32 days to replace my steering box 4 years ago. (I know, what kind of sh*t is that???)

    Thanks
     

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  2. BadDNA

    BadDNA hophead

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    Check the wiring for the O2 sensor. I had one pop up on a car I used to own, turns out when I crawled underneath to replace the sensor I found that a couple of the wires had been wearing on the frame in a spot that they weren't protected and they were shorting out. Spliced the wires, covered with some wire loom and all was good.
     
  3. Westy

    Westy the teste

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    I had a car do something like this a while ago. O2 sensor would get a bunch of carbon build up on it and throw up O2 sensor codes. Clean it off with compressed air and it would run well for a while. Obviously something else was wrong but checking and cleaning the O2 sensor is a quick and easy way of seeing if it is something else.
     
  4. 5150dhbiker

    5150dhbiker Turbo Monkey

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    Does not really help you too much but I've gone through 4 O2 sensors in my Tacoma over the past 2 1/2 years :~ Kind of weird that they keep failing.

    If I were you, I'd take it to some place other than Nissan to have them check it out. Stealerships suck!
     
  5. Jim Mac

    Jim Mac MAKE ENDURO GREAT AGAIN

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    My mechanic got me a "pre-owned" 02 sensor a few years back and it still works well.
     
  6. Sandwich

    Sandwich Pig my fish!
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    i'm with the teste...check an old 02 sensor, preferably the second one, and see if it's dirty or just busted. If it's dirty, like black soot dirty, something is possibly wrong with the fuel/oxy mix, and the car is running rich...or you're burning oil.

    Outside of that, i'm at a loss. good luck!
     
  7. TSchultz

    TSchultz Chimp

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    Some vehicles have up to 3 O2 sensors are they replacing the same one every time? It could be one of the other ones.
     
  8. Haywoodublowme

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    Does the truck have two o2 sensors before the cat? Have both been checked?
     
  9. C.P.

    C.P. Monkey

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    There are a few things that can cause an P1163 O2 sensor code other then the sensor being the problem itself. Check the wiring to the sensor, then if possible clean the sensor.
    While your under the hood, it aint a bad idea to clean your MAF sensor (at the intake).

    A quick search uncovered this little article... seems like a grounding issue. that has been reported with this model. Nissan recommends a fix for a poor ground to the intake where the (O2 and other) sensors are grounded. It looks like they want you to backup the existing ground by adding some ground wires to another location closer to the negative cable.

    At worst case, it could be a leaking head gasket or even worse, cracked head or leaking exhaust manifold. typically cats dont "go bad" that easily. I have my doubts that a cat could be the prob.
     
    #9 -   Feb 12, 2010
    Last edited: Feb 12, 2010
  10. Westy

    Westy the teste

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    I used to drive around with a used but clean O2 sensor in my glove box. Car would be driving along just fine then start puking black smoke and the CEL would come one. Would swap the 02 sensor on the side of the road. Clean the old sensor and stick it back in the glove box for the next time it puked.
     
  11. C.P.

    C.P. Monkey

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  12. Kanye West

    Kanye West 220# bag of hacktastic

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    If it's accessible, put some baby powder around the header mounts to check for leaks there. Check grounding for 02 sensors.

    If your mixture were actually so far off it'd be fouling sensors, you'd have other error codes.

    Does your mileage drop before or after it pops up the error code?
     
  13. johnbryanpeters

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    OK, try it now.
     
  14. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Mileage seems bad all around. I'll check the ground on it.
     
  15. eaterofdog

    eaterofdog ass grabber

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    You haven't used silicone lube anywhere under the hood have you? That stuff kills O2 sensors dead.
     
  16. Kanye West

    Kanye West 220# bag of hacktastic

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    Silicone lube? Explain?
     
  17. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Working on this now. I hope this is it.
     
  18. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Have not.
     
  19. DirtyMike

    DirtyMike Turbo Fluffer

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    CP is on the right track on these. Lots of grounding issues with these, its not the sensors themselves<which arent really called o2 seonsors on that model, but rather a fuel ratio meter....ALOT more accurate, and read a bit different>.

    Im going to recomend a product here, Stabalint 22, its a little costly, but damnit if it doesnt works absolute wonders on ele connections. One drop per connection, one bottle is about three ounces, runs about 30 bucks... it goes a long ways though. Its purpose is a simple one...... it makes a better connection. It suspends dirt, rust ETC in it when you use it, gives the best possible connection you can get.

    I use it on ground connections, splice connections, frame connections...everything.


    Ok another list of items that will also cause this to happen,

    Vacuum leaks
    Dirty MAF
    Faulty coolant temp sensor<in range, but not the right temp>
    Exhaust leaks<I use a tennisbal wrapped in a shop wrag to find them easily>
    Changing out just a single O2
    Dirty fuel injectors that are dripping instead of atomizing
    valve adjustment<think this model is a hydraulic tappet so this doesnt count>
    Intake air temp sensor


    So as you can see, its alot more than just looking up on the scanner and replacing the part that corosponds to the code, there are very few codes that are that direct. With the milage symtoms, I am in serious doubt you have an o2 problem, but something causing a fuel mixture problem. First place I would be looking is the MAF, before you do anything else, go there.


    Little breakdown of how the PCM reads O2's, and the setup.

    All OBD2 vehilce have at least two for four cylenders, three for anything not inline. One before the Cat, one after. If it has two cats, itll have four o2's. The upstream o2's read and moniter the fuel mixture, and compare to each other to make sure they are in range with each other. If one is slower than the other, youll get a code, if one isnt heating fast enough, youll get a code<electric heater, should be hot in less than 30 seconds> there is the problem with replacing just one upstream O2, as they age, they do slow down, you replace one and now you have one thats fast, one thats slow.... youll get another code for a slow responce for the one that hasnt been replaced. Your downstream o2s do but one job....Moniter the cat converter. The signal from the Downstreams should be relatily steady, if the cats working, itll be an extremly steady unlike the upstreams which are continuesly going rich.lean. once the Downstream starts going rich/lean<crosscounting> it sets a code for catalyst below threshold.


    Ill look up the code you listed, and see if anything else comes to mind off hand.
     
  20. DirtyMike

    DirtyMike Turbo Fluffer

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    Oh, and teh silicone lube thing.... thats bunk, most spray lubes, spark plug lubes, oring preps ETC are all silicon based, I use it all the time, its been proven to be all sensor safe.
     
  21. DirtyMike

    DirtyMike Turbo Fluffer

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    Ok...just did some checking, First off, so you know.... P1163 is a Nissan specific code, if its read with the wrong scanner, itll give the WRONG info as to what it is......

    this is not an O2 code, this is fuel trim not operating properly, meaning that the PCM cannot compensate for an overly rich condition. You have a couple options here

    Stuck open fuel injector, dirty injector tip, fouled MAF, Faulty fuel pressure regulator, Leaking diaphram pouring fuel into the intake system, Pull the vacuum line off it, if it its wet in the line, thats yourdoggie>...IMO replacing your O2 did nothing to help, and My guess is itll be black and fouled it you were to take it out, Im thinking they used a generic OBD2 scanner which gave misleading info and an improper diagnostic.


    Still looking for some conclusive info for ya..... give me a bit


    EDIT....BTW I found four different definitions from other MAnf's for the same code. Any code that starts with a 1 after the P is a MAnf specific code, anythat starts with a 0 after the P, is a global code<those are the only ones that are teh same from Car to Car>




    Second EDIT.... Not having much luck with open internet for info, If I have a little free time Ill dig into Michell tommorrow.
     
    #21 -   Feb 12, 2010
    Last edited: Feb 12, 2010
  22. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    The weird thing is that it acts like it should be rich, but it's super lean, according to the mech. I'm taking it back on Monday to look into the ground issue. I cleared the code again and it hasn't come back for 30 miles this time. I may take it on a road trip tomorrow. Hopefully I won't be needing to have it towed from two hours down the road.
     
  23. Westy

    Westy the teste

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    You should take it to Mmike's mechanic.
     
  24. DirtyMike

    DirtyMike Turbo Fluffer

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    Ok, I gotta ask, what are you doing to clear the code..... Please Please Please...tell me your not pulling the battery then taking it into the tech with it cleared.... thats a surefire way to never get it right


    Oh, and with milage dropping, I doubt its running lean.
     
  25. DirtyMike

    DirtyMike Turbo Fluffer

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    Oh, and BTW, the big tip off that it really isnt an O2 problem truly is the milage. I have yet to see an O2 actually make a noticable impact on milage on an OBD2 vehicle, everytime I have had those tow in combination, I find something else to be the fault, and the )2 codes to be a side effect of the root cause<See the list about for what can cause rich conditions> The reasoning behind this.... the O2 can only control fueltrim/ fuel mix sooo much before it just goes out of range, and teh PCM goes to a default which isnt a drasic drop like your noticing. The drastic drop in milage is teh root cause of your problem, not the O2
     
  26. SkaredShtles

    SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    It wasn't a drastic drop... he was only getting 14mpg before. :rofl:
     
  27. Rip

    Rip Mr. Excitement

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    Try it now!!!
     
  28. blackohio

    blackohio Generous jaywalker

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    whats the voltage on the o2 sensors reading at? are they switching on/off? Is the code specific to the sensors?
     
  29. DirtyMike

    DirtyMike Turbo Fluffer

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    Without modification, thats a decent and noticable drop in milage.
     
  30. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Going to check that on Monday.

    Mike...the levels for fuel are below .5, whatever that really means. They assure me it's lean, which is what really makes no sense.

    To clear codes...I have a consumer computer I use to clear it. I haven't been clearing them when they go to the shop, but since I know it's the same issue, I have cleared them until I get to the shop. Tired of that f*#king light. :rant:
     
  31. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    You and the old bastard both suck at fixing it. Still broken.
     
  32. DirtyMike

    DirtyMike Turbo Fluffer

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    You mean the O2 signal is staying below half a volt? because if thats the fuel trim number its not rich or lean, Ideal fuel trim is zero, plus or minus five. Most bevicle will lit up the engine light around either a positive 14 or a negative 14 for a rich or lean condition.

    Now about you clearing the codes... i have to switch my train of thought now, you could in fact be masking the problem, and inducing the mileage by clearing it. Those global readers dont just clear the codes, they also clear the keep alive memory<Kam>. So when your clearing it, you've just erased all the info and fuels trategies the vehicle has learned to compensate for each driver.....

    Anyways, What engine is in this bad boy? Ill give mitchell a look today for any info, or possibly TSB's that may help
     
  33. Brian HCM#1

    Brian HCM#1 MMMMMMMMM BEER!!!!!!!!!!

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    Duct tape should be able to fix your issues.
     
  34. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    Pretty sure it's a 3.3L V6. I know it's a V6, but foggy on the engine size. No turbo.

    This all makes my head hurt.
     
  35. SkaredShtles

    SkaredShtles I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!

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    Not to a Texan. :disgust1:
     
  36. C.P.

    C.P. Monkey

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    For the ground issue, just get a $10 multi tester that measures ohms, and test the readings between: (make sure your down to bare metal when testing)

    -engine block & unibody/frame
    -unibdy/frame & battery negative.

    If you read anything higher than 0 Ohms, you have a poor ground between engine & battery neg, which causes OBDII engine sensors to go haywire...this should take 3 minutes to check...(make sure your meter has a fresh battery - been there donethat)
     
  37. DirtyMike

    DirtyMike Turbo Fluffer

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    Ohms are a crappy way to check grounds. Do a voltage drop instead....... You can chase ohms for days, and never see whats actually happening. a Voltage works better because your checking the system running, not static. In other words, your checking it with a load vs unloaded.

    A circuit can have less than .025 of an ohm resistance, but still be unable to carry the load of an operating signal..... take a bundle wire<stranded style, lets say 50 strands> All but one has broken, itll still be in spec for ohms reisstance, but when you load it, youll get a voltage drop. Only way to go with electronics.

    Basically, youll put your meter on DC voltage, put one lead on the neg post<post, not the cable, then one lead on the wire side of the ground...ideally you will get a zero reading, thats a perfect ground... the more resistance there is, the higher the voltage youll get.... should be no more than 2.5V at max, and even that is a bit much, I like to see less than .5V when I do this......I also usually start with doing this from the battery post to the cable end first to make sure what I am losing right there, if its bad, I fix that first, then I figure the voltage drop from the cable into the total number for the circuit being tested.....









    Loco, super busy today... never had any time to slow down at all.... Ill make it a point on Monday
     
  38. C.P.

    C.P. Monkey

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    Interesting. I'm not even close to an expert with electronics, but doesn't ohms law say were taking essentially the same measurement? (voltage drop is directly proportional to resistance {or ohms}) I dont do this enough to really know which way is better or why...
     
  39. Westy

    Westy the teste

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    Ohms law (V=IR) pretty much holds up under any circumstance for a good conductor like a copper wire would be. The exception would be when an excessive current heats up a wire, the resistance increases with temperature.

    Insulators on the other hand tend to have a voltage where the law breaks down. Under high voltages the electrons move to a much higher quantum level and can become conductive. There is something called a megohmmeter. It basically applies a very high voltage to an OPEN circuit and checks to see if any current bleeds off due the insulation breaking down.

    The laws aside what DirtyMike recommends isn't a bad idea. I think it is a good idea to see what is happening while things are running. An O-scope would be the ideal measurement device. But I still don't think it would point out a resistance issue? Don't deal with cars that much but with the suff I've worked on, a voltage floating around on a ground was usually cause by some weird noise or ground loop problems..
     
  40. johnbryanpeters

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    The resistive temperature coefficient of copper near room temperature is +0.393 percent per degree C. You'd have to heat it up rather a lot to get a noticeable difference.