O2 sensor for headers??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BLzr4x4ngkid, Mar 20, 2000.

  1. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

    Feb 18, 2000
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    Wichita, KS
    What exactly does an O2 sensor do?? I have an TBI Jimmy('87) and I want to put dual exhaust on it and everyone has told me that an O2 sensor is needed. Where can I get one and how do I get it on the headers?? Some stuff I know, but this has blown over my head and keeps going. Tell me something about it and how I get it on the headers and in the BEAST. Thanks


    "What me get stuck? NEVER!!"(Famous last words)
  2. Blazer1970

    Blazer1970 1/2 ton status

    Feb 17, 2000
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    Old Mission, MI
    The o2 sensor puts out a voltage that tells the computer whether your engine is running lean or rich. This signal, along with the throttle position (from the TPS), and the manifold absolute pressure (from the MAP sensor), tells the computer how much fuel to squirt out the injectors to make your engine run right. You should be able to use your existing o2 sensor with the headers (it is screwed into your driver's side exhaust manifold). Headers are available with a boss already installed for the sendsor, or a welding shop could add the boss to a header that does not have it. You might have to extend the wire to the sensor.


    1970 Blazer CST 4X4 350 SM465 NP205
    1987 Suburban 4X4 350
    1988 Chevy Pickup 4X4 350
  3. turbo

    turbo 1/2 ton status

    Feb 18, 2000
    Likes Received:
    O2 sensors come in muptiple flavors.
    Some new cars have "wide band sensors that are very expensive"
    Cheepest are one wire better are 3 wire with built in heater.

    A bung which can be welded into exhaust pipe cost around $6 from summit. Then the sensor just screws in.

    Sensors cannot tollerate leaded gas.

    Sensors only operate at very high temp so heated sensors with a built in 12 volt heater work better with headers.

    The 3 wires are
    1) a ground
    2) A ignition switched +12 for the heater
    3) The actual sensing wire.

    The O2 sensor generates a voltage (when suficiently hot) from 0 to about 1.2 volts wrt outside of sensor (ground).
    The higher the O2 concentration the lower the voltage.
    Ideal mixture is aprox .5 volts.
    Once car is warmed up unless you have low vacuum large opening of throttle the EECS adjusts injector pulse to stay around the .5 volt sweet spot.
    It increases injection pulse if voltage is below .5 and decrease pulse duration if above .5 volts with continual adjustments the keep sensor voltage constantly crossing back and forth over the .5 volt sweet spot thus keep ing an ideal mixture for both power and emiosions.
    This lets it automatically adjust for altitude changes.

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