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Heated or Non-Heated o2 sensor?

Discussion in 'The Garage' started by JEBSR, Mar 12, 2007.

  1. JEBSR

    JEBSR 1/2 ton status

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    I was looking at a website that sells performance equipment for TBI vehicles and ran across this http://www.cfm-tech.com/catalog/oxygen_sensor_-_3_wire__heated__549479.htm . Yes I have full length headers, yes I know the difference between the heated 3 wire sensors and the non-heated single wire sensor like I have. My question is: how will this improve my trucks performance or emissions? Is it worth doing?
     
  2. mr.smartass

    mr.smartass 1 ton status Premium Member

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    I had to install a 3 wire because my exhaust wasn't heating the O2 sensor enough and it kept surging and doing crazy things, going in and out of open and closed loop or whatever. It totally fixed all of my problems, if you aren't noticing any problems then I don't really see a point...
     
  3. JEBSR

    JEBSR 1/2 ton status

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    The only problem that I have is that when hot and taking off slow it seems to retard the timing around 1200 rpm. Once I reach 2300 it is like hitting a switch and it comes to life. If I step on it hard it will go fine. The hotter it gets the worse it gets. I'm pretty sure my est module is bad though, and that is what I believe is causing it.
     
  4. sled_dog

    sled_dog 1 ton status

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    my suburban always sputtered and ran like crap off idle and off the line on acceleration. Until I put in a 3-wire, it was a nigh and day difference for the cold running of the engine.

    I can't say that my engine ever really got into closed loop before I put in the 3-wire, even cold it didn't run as good as it did when I put that 3 wire in.

    Your hot issue however, is more likely something else.
     
  5. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    You want the heated sensor if it's being used by a computer to control your engine. O2 sensors can output erroneous readings when they are cold.

    Basically, the unheated type is only good for a simple air/fuel gauge that a human would read, and is able to process the fact that if it's at 0 at idle, then it's probably not hot enough to read.

    I have the cheap summit air/fuel gauge with an unheated o2 sensor on my '86 C10 with 4.3l V6 carbed, on a cold day at idle, or a warm day when I first start it, it reads nothing or pegged out, until I rev the engine a bit, then it starts registering.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    unheated was ALL GM used from 1980 up until at least the late 80's.

    It simply takes longer for the vehicle to go closed loop than with the heated.
     
  7. JEBSR

    JEBSR 1/2 ton status

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    Well thanks for the replies. I think I'll stick with the one wire for now. I'm thinking about doing a BBC swap within the next year so I will just do the swap then.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    You really need to have a scanner on it and watch to see if it's going closed loop. It won't go closed loop if it's cold, and headers CAN lead to that. Not always, but it is common.

    If it runs good enough for you, and you plan on doing the swap later anyways, just leave it. They are fairly pricey to do "just because".
     
  9. JEBSR

    JEBSR 1/2 ton status

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    Thanks, once I get home I will check it to see if it is going closed or not. Pretty sure it is and it runs great other than my possible EST problem when hot (also has to be hot outside as well). As soon as I get home I'm going to start looking for a multi port 454. If I cant find one reasonable I will just freshen up my motor and change the sensor out then.
     
  10. sled_dog

    sled_dog 1 ton status

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    I never realized it until I put the heated sensor in my Burb, but with the long tubes and 1 wire, I am pretty damn certain I was never going into closed loop.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes, they can run quite well in open loop, it really depends on the engine. With engine mods it's LESS likely to run good in open loop, but again, a scanner watching to see if it goes closed and stays there is about the only way to know for sure.
     

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