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screwed up and failed smog

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by k5geezer, Jul 21, 2002.

  1. k5geezer

    k5geezer Registered Member

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    Got labled a gross polluter for failing nitrous oxide emissions. HC was 10-20% of allowable, CO measured 0%, but NO was way high. After failing, did a search on this site and saw recommendatins to get a pre-test. Too late now. The EGR passes all the diagnostics in the GM manual, however, hooked up a vacuum gage to the EGR port so I could read it while driving. The EGR gets vacuum when accelerating but it kicks out during cruise. I guess it kicks out on the smog treadmill test too. No codes show up and timing is set at zero degrees.
    Any ideas what I should look for next? Would methanol or one of the drug store addatives help reduce Nitrogen emissions? Thanks in advance for any replies.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Lowering combustion temps will help with NOx. So will a cat converter. (somewhat) Alcohol will work if it burns *cooler* than gas, but I don't know the answer to that one.

    EGR helps NOx as well I thought by bringing down combustion temps. If you have an EGR problem, you should probably get it fixed. Should be *open* at a steady cruise.
     
  3. k5geezer

    k5geezer Registered Member

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    Does anybody know if alcohol or other fuel additives will help pass NOx with a TBI motor?
     

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