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87' exhaust tubes

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mattyblazer, Oct 6, 2002.

  1. mattyblazer

    mattyblazer 1/2 ton status

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    87\' exhaust tubes

    will my truck run rite if I bypass the pollution tubes in the stock manifols?
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: 87\' exhaust tubes

    Yes it will run fine, but unless they are defective (as in rusted out and leaking, like they do) there is no point in removing them, the AIR system doesn't cost you anything noticeable in HP, and will make you fail a visual inspection, whether you have to pass one now, or in the future.

    don't think truck cat converters had an AIR fitting on them (my 83 didn't at least) but if yours does, thats something else to think about before yanking it.

    AIR system is "downstream" of all engine sensors except O2, and AIR is re-directed to the cat converter (or air cleaner if no cat converter fitting I presume) after warm up (closed loop) anyways.
     
  3. mattyblazer

    mattyblazer 1/2 ton status

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    Re: 87\' exhaust tubes

    I got headers, and they shipped the ones without the tubes, so I dont care about the visual inspection I just want to know if the O2 sensor will run rite?

    Thanks
    Matt
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: 87\' exhaust tubes

    O2 will "run right" as long as you have the sensor in the right place : )

    Some people have problems with the O2 sensor "cooling off" with headers, which is due to the length away from the heads, the remedy is run a heated sensor. Your mileage might go to crap though if this is the case, a scanner will tell you too, you'll see it drop out of "closed loop" when the engine is idling, hot. Again, thats ONLY if the O2 sensor is getting cold.
     
  5. mattyblazer

    mattyblazer 1/2 ton status

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    Re: 87\' exhaust tubes

    Thanks again, I was not aware that they made a heated sensor for tbi, I will look into getting one or just switching the headers with the correct holes for the tubes.

    I had an 81' suburban that the tubes rotted out on, and just capped the holes in the manifols, but that was a carb application and I just didnt want trouble with the computer.

    The reason I considered losing the tubes was taking the belt off the pollution pump, any gain is a good gain?
    Lately I feel like a 20 year old in the speed shop with an iroc z... I cant believe that I am buying headers, transmission kits, MSD ignition, and hypertech chips again, I thought them days were long gone. Its good to feel like a kid sometimes.

    Thanks,
    Matt
     
  6. trailblazer87

    trailblazer87 1/2 ton status

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    Re: 87\' exhaust tubes

    The heated sensor is from a mid-90's 4.3 v6. There are four wires, one goes to the original wire, the others are for power. Can't remember which one goes where though.
     

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