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HELP O2 sensor and headers Question!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 87superblaze, Feb 28, 2002.

  1. 87superblaze

    87superblaze 1/2 ton status

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    I have an 87 350 TBI and I put hooker headers with 3" collector tubes. I eliminated all the smog tubes and air pump (sshhhhh!) The headers didn't come with holes for an oxyen sensor so I welded a washer over a hole I cut and threaded the O2 sensor to that.

    I have been getting a code popping up that says there is something wrong with the sensor. It only comesup once in a while. It's a new Sensor!!

    What could possibly be wrong with what I did? Seriously!
    Is there such a thing as a "depth" saying how far the sensor should stick in to the tube?

    Please I need help. I am going to rebuild the whole motor during spring break and I need to know what to do while the motor is apart, case I need headers with O2 adapters.

    My Truck <a target="_blank" href=http://www.community.webshots.com/user/nicksm79>http://www.community.webshots.com/user/nicksm79</a>
     
  2. TopOff

    TopOff 1/2 ton status

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    Mine actually sits rather high outside the header. I think only about 1/2 the sensor is actually in the exhaust, yet it works.

    What is the code? 44? 43?

    Do you know if you get the code when cold? Warmed up?

    <font color=red>Roads, where we're going we don't need...roads. </font color=red>- Doc.
    '73 Blazer, 383 - 3/4 ton, ARB F&amp;R, 35"<P ID="edit"><FONT class="small">Edited by TopOff on 02/28/02 03:26 PM.</FONT></P>
     
  3. 87superblaze

    87superblaze 1/2 ton status

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    Honestly, I don't know what code it was. All I know is that is said something along the line that my O2 sensor was bad.

    It mostly happens when it is warmed up. The motor also has 170,000 miles on it, if that makes a difference.

    My Truck <a target="_blank" href=http://www.community.webshots.com/user/nicksm79>http://www.community.webshots.com/user/nicksm79</a>
     
  4. HarryH3

    HarryH3 1 ton status Author

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    Check the error code again. A check engine code doesn't mean that the sensor is necessarily bad, just that the computer doesn't like the info that it is getting from the sensor. The code should be for either too rich or too lean. The computer may not like the fact that the air injection is gone now. That means that less O2 is in the exhaust stream, so the O2 sensor may be reading that the mixture is too rich. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  5. 87superblaze

    87superblaze 1/2 ton status

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    So does this mean that it will hurt my engine since the sensor is telling the computer that the mixture is too rich? Would this cause my mixture going in to the engine to be too lean an harm the engine??

    My Truck <a target="_blank" href=http://www.community.webshots.com/user/nicksm79>http://www.community.webshots.com/user/nicksm79</a>
     
  6. TopOff

    TopOff 1/2 ton status

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    There are many sensors that could be giving you the check engine light. Case in point, are you getting a CHeck Engine Light or a O2 light?

    If the O2 is telling the computer that it is too rich, the computer will lean it out. The the O2 will tell the computer it is too lean, and richen it. This is simplified, but you should not have a too lean, or a too rich condition for very long.
    If you do get a too lean or a too rich condition for over (I think) 1 minute, you will get another code, and a check engine light.

    <font color=red>Roads, where we're going we don't need...roads. </font color=red>- Doc.
    '73 Blazer, 383 - 3/4 ton, ARB F&R, 35"
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    You *may* not be keeping the O2 sensor hot enough. It seems like a fairly good idea on all applications to go to a heated O2 sensor, especially when making your own application. Of course figure out what the code is first.

    As to AIR, no it doesn't matter. AIR is injected into the manifolds during "open loop" (hence the divert valves) and into the cat converter during closed loop. You CAN hurt the cat though. (if you have a cat with a fitting on it) If AIR was injected into the manifolds during closed loop, you'd end up with an O2 sensor "reading" more O2 than was actually present. The ECM would continually try to enrich the mix, even though the mix going INTO the motor might be perfect, it would "see" too little fuel compared to O2.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  8. 87superblaze

    87superblaze 1/2 ton status

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    Thanks everyone. I completely forgot about a *heated* O2 sensor. That maybe my problem.

    Can I get one of these heated O2 sensors at the local parts store?

    My Truck <a target="_blank" href=http://www.community.webshots.com/user/nicksm79>http://www.community.webshots.com/user/nicksm79</a>
     
  9. HarryH3

    HarryH3 1 ton status Author

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    Do the trucks divert air to the cat? I've seen that on cars, but none of my GM trucks have had an air tube to the cat. They just inject air into the exhaust stream right at the ports from what I've seen.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
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  10. dyeager535

    dyeager535 1 ton status Premium Member

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    I was under the impression the TBI trucks had AIR to the cat converter. Is there an additional pipe on anyones TBI original cat converter? Not quite sure how an O2 sensor system could operate correctly without AIR divert....


    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  11. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    I had this exact same problem when I put my Edelbrock TES headers on. Ran great until it hit closed loop then like crap unless I drove it hard for a while and heat the o2 sensor up enough. Then I'd sit at a light it would start running crappy again and this was during the summer in phx. I ordered a generic 3 wire heated o2 senser from somewhere on the web for 40 bucks and it runs great now.... Well besides the fact the motor isn't in the truck right now.

    Mike.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Some have had problems with aftermarket non-heated O2 sensors acting the same way, even in stock locations, stock non-heated. A swap back to a new Delco sensor solved their problem as well, but when changing exhaust config, I'd probably consider a heated sensor necessary or at least desirable.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  13. HarryH3

    HarryH3 1 ton status Author

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    My '87 K5, my '91 S-Jimmy and '94 Suburban didn't have the pipe to the converter. The '87 Corvette that the engine in my '75 K5 came from did have air to the converter. That's why I was thinking that the trucks didn't come with that "feature".

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Hmm...perhaps it was "vented" into the air cleaner after warmup, as I do recall some air cleaners with two large ports in them. If you've owned them, you'd know better than I. That would make one less reason to keep AIR. : )

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  15. HarryH3

    HarryH3 1 ton status Author

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    The 'vette engine vents via a small muffler behind the pump when it isn't sending air to the exhaust or the cats. They divert the air away from the exhaust stream during decelleration to prevent exhaust popping.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     

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