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emissions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by t's85chevyk5, Feb 9, 2004.

  1. t's85chevyk5

    t's85chevyk5 Registered Member

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    I have an 85 k5 with a carbuerated 305. Every thing dealing with the motor has been kept to the stock setup. I recently changed my egr valve but i still failed on my NOx levels. Every thing else is very low. does any body have an idea of what the exact problem is or what it would need to pass? My vehicle s emissions on nox levels were 7.42. The amount allowed is 7.00

    thanks fellas
     
  2. Confedneck

    Confedneck 3/4 ton status

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    i hear 20 bucks helps you pass. LOL we dont have emissions checks here in florida.. i remember hearing about "drygas" to lower one of the emissions..
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    What timing set at? Did you adjust carb? I have ran mine through emissions in Maricopa County twice and passed with less than the half the allotted amounts . I don't have too much time this week but I am sure if you could make it to Mesa I could look at it with ya. I basically run stock setup also, with a little hose cleanup underhood.
     
  4. t's85chevyk5

    t's85chevyk5 Registered Member

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    my dads buddy is going to put the sniffer on it today. Maybe he could figure it out. I was just wondering if anybody had simmilar problems. I appriciate you trying to help, but i cant make it to mesa this week because of work and school. /forums/images/graemlins/waytogo.gif
     
  5. R72K5

    R72K5 Banned

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    theres not much you can adjust on 80s smogger carbs cept for idle speeds and choke, the mixture screws are sealed and you arent supposed to touch them
    do you still have EST Q jet and HEI setup intact ?


    good luck
     
  6. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Well NOx is caused by heat, and heat when the EGR valve doesnt open. You said youve replaced it, check everyhting before the EGR, and make sure its opening up, when it does the NOx should drop off!
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    If it's a non-dyno test, EGR shouldn't be working, FWIW.
     
  8. tungsten

    tungsten 1/2 ton status

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    This is an interesting thread and hits right at home with me too. I ran my 1985 K5 through emissions two weeks ago and failed it due to a excessively high carbon monoxide reading.

    I guarantee it's the first time this truck has ever been through an emissions test since it rolled off the factory floor, and God only knows if the AIR pump still works or not. /forums/images/graemlins/grin.gif

    Anyone want to take a stab at why it's got such a high CO reading? I'm going to either have to pour some isopropyl alcohol into half a tank of gasoline and run it back through again. Supposedly that will let me pass the test; which is cool because I'm yanking the 305 out and dropping in a 350 by the end of April anyway.
     
  9. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Well I wish you luck and the offer still stands. If its that close to passing it can be done. Try running it a little leaner /forums/images/graemlins/k5.gif
     
  10. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    If it failed for CO, then its running rich, check the air fuel ratio.
     
  11. tungsten

    tungsten 1/2 ton status

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    [ QUOTE ]
    If it failed for CO, then its running rich, check the air fuel ratio.

    [/ QUOTE ]

    I thought the stock carbs on these smog trucks couldn't be adjusted. How would I adjust the air fuel ratio?
     
  12. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Oh it has a feedback carburetor?
     
  13. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    [ QUOTE ]
    I thought the stock carbs on these smog trucks couldn't be adjusted. How would I adjust the air fuel ratio?


    [/ QUOTE ]
    If the carb is NOT a feedback (electric) carb then you could could pop off the blocking plugs on top of mixture screws(easier if carb removed) and use the tool napa sells to turn mixture screws. /forums/images/graemlins/thumb.gif
     
  14. tungsten

    tungsten 1/2 ton status

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    Cool... thanks. I think I will just push forward and swap the new 350 into the Blazer and fiddle with the shiny new Edelbrock carb instead. /forums/images/graemlins/grin.gif
     

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