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Thread: Need help on passing smog on our car

  1. #1
    Join Date
    Jun 2011

    Default Need help on passing smog on our car

    We have a 1999 oldsmobile alero 4cylinder.I've taken it to smog 3 times but it just won't pass.These are the two reasons that are holding me back from passing. 1Hydro Carbons(HC) 2Oxides of Nitrogen (NOx).What do I have to do to make it pass??

  2. #2
    Join Date
    Jan 2007


    Hello blurobles,

    Refer to Chapter 1 for tune-up information. Also, refer to Chapter 6 if you have a check engine light that has recently been on. If you have done all of the tune-up work and you still have high emissions, you'll need advanced diagnostics and we recommend professional assistance. You can also get some ideas by doing some online research for your vehicle condition. Without getting too technical, hydrocarbons are unburned fuel, NOx is a result of combustion but there are engine conditions which can drive this number higher... Here is an example of what I mean (Link below):
    http://www.smogtips.com/failed-high-hydrocarbons-HC.cfm (copy and paste if necessary).

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