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O2 sensor...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90blzr, Jul 10, 2001.

  1. 90blzr

    90blzr 1/2 ton status

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    How do you know if the O2 sensor is bad or not. I dont know how long it has been since mine has been changed, at least a year cause I havent done it. Anyways is it just something you replace with every tune up or is there a way to tell if it is good or bad? And it is located on the exhaust manifold right and is there only one? What does it do exactly anyways(might be a dumb ?, but I wont know unless I ask) Getting ready to do the normal tune up stuff and was just wondering about that sensor. Thanks.

    <P ID="edit"><FONT SIZE=-1>Edited by 90blzr on 07/10/01 10:13 PM (server time).</FONT></P>
     
  2. Pugsley

    Pugsley 1/2 ton status

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    I like to replace them whenever I do a tune-up - a good rule of thumb is every 50K miles. There's really no way to test them at home, so I'd say just chunk it and replace it.

    <font color=red>Cripplefight!!</font color=red>
    <A target="_blank" HREF=http://pugsley.alloffroad.com>http://pugsley.alloffroad.com</A> Updated finally[​IMG]
     
  3. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    They're cheap too.

    "I am Republican. Not a baby-killing, tree hugging, land grabbing, touchy feely, hypocrite wuss democrat!"
     
  4. newyorkin

    newyorkin 1 ton status

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    If it's bad, the computer will throw a code, 13 I think, but I'm probably wrong.
    But it is a good thing to change with every tune-up. It loses accuracy after some mileage...

    Ratch
    <A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A>
    **K5 - What more is there to life?**<P ID="edit"><FONT SIZE=-1>Edited by newyorkin on 07/11/01 07:56 AM (server time).</FONT></P>
     
  5. MudFrog

    MudFrog 1/2 ton status

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    I believe you are supposed to change the O2 sensor when you put a new CAT on. I'm sure you should do it more as well but deffinitely with a new CAT. I just pulled mine and I could tell by looking at it that it has seen better days.

    89 K5 Silverado
    <A target="_blank" HREF=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</A>
     
  6. 88streetblaze

    88streetblaze 1/2 ton status

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    the manuals recommend replacing it every 60,000 miles...
     
  7. Stoopalini

    Stoopalini 1/2 ton status

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    Every 60k is about right for replacement.

    The O2 sensor is located in the manifold or headers and you should have only one of them. The ECM uses the data from the O2 sensor to set the air/fuel mixture on your TBI.

    If the O2 sensor goes bad, the 1st indication will be a noticable loss in fuel economy. The computer will not always throw a code when the O2 sensor goes bad; Sometimes it will, sometimes it won't.

    On my camaro, I got a code 44 (lean mixture) from a bad O2 sensor. The sensor gets clogged up and starts reporting that the exhaust is too lean. Because of this, the ECM will compensate by making the mixture too rich. This is why your MPG is the first thing to suffer from a bad O2 sensor.

    If you think it's bad, just replace it. They're cheap enough.

    Thomas.

    -- '84 K5 Blazer --
     
  8. Executioner

    Executioner 1/2 ton status

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    Got a propane torch, and voltmeter ?
    If yes then you can test them at home !
     
  9. Executioner

    Executioner 1/2 ton status

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    You must have one of those calibrated eye balls !!!!!!!!!!!!!!!!!!!!
    NOT
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I have always used an occilliscope to test them. Every time I've tested an old one, it's bad. Replace it, re-test, and it puts out the proper waveform and works wonderfully.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Use a GM one. Heard nothing but bad news about the aftermarket ones (Bosch, etc.) although some I'm sure have had no problems.

    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  12. rampage

    rampage 1/2 ton status

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    If you pull it out to test it then why not spend the $12 and toss in a new one?
     
  13. newyorkin

    newyorkin 1 ton status

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    $12???? Where do you shop?? Mine was $30 2 months ago up here on Long Island!

    Ratch
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    **K5 - What more is there to life?**
     
  14. rampage

    rampage 1/2 ton status

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    $30? Hmmm, don't remember paying that much, but I bought mine about a year ago so my memory could be slipping.
     
  15. Executioner

    Executioner 1/2 ton status

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    can you plese describe the waveform ?
    TIA
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    We didn't pull them out to test them. We probed the wires. How could you test if it was working anyway unless the engine was running.

    Executioner,
    The waveform looked like a sine wave. It would go lean for a split second, the computer would make an adjustment, it'd go rich, then make another adjustment, etc. The bad ones didn't make any waveform at all. The shape of the waveform wasn't all that important, as long as it showed that the sensor was operating. Like I said earlier, none except the brand new one ever registered a thing.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  17. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    Just replace it... you don't know for sure if it was replaced or not before you got it. Chances are not... they are like $30-$35. It can make a difference in how your truck runs.... I just bought one, it's by Standard. I'm replacing my whole exhaust and figured it was time! Get a new one and then you can be sure it's working right....

    BTW I have an 86 and the part # is SG5. I'm not sure it'll work for you, but if it does then you could use it [​IMG]

    I removed my quote so gay, vegetarian, minority, eco-nazis who love Jesus, nuke spotted owls, vote Gore and smoke medical marijuana won't be offend.
     
  18. MudFrog

    MudFrog 1/2 ton status

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    I sense the sarcasm... but majority of my blazer still had factory goodies under it when I bought it. And this O2 sensor was looking pretty bad. Granted yes it might have still been good... but I highly doubt it.

    89 K5 Silverado
    <A target="_blank" HREF=http://mudfrog.rockcrawler.com>http://mudfrog.rockcrawler.com</A>
     
  19. Executioner

    Executioner 1/2 ton status

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  20. Executioner

    Executioner 1/2 ton status

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    It is ok to replace parts that look bad ! But its more fun to test them first, with home made tools !
    And learn from it, wish I could afford to replace all bad looking parts on my K5.
    Keep up the good work, its all part of the learning process.
    Good luck
     

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