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Thread: smog results

  1. #1

    smog results

    Just had my smog check on '94 Lincoln Mark VIII. It passed.

    All results looked great, except at 15 mph the HC ppm measured 57 and the max allowed is 57.

    What would cause the higher reading?

    Test giver said it measures incomplete combustion.

    At 25 mph, the max is 33, and it measured 7.

  2. #2
    Vulture of The Western World Eric's Avatar
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    Quote Originally Posted by pearly8 View Post
    Just had my smog check on '94 Lincoln Mark VIII. It passed.

    All results looked great, except at 15 mph the HC ppm measured 57 and the max allowed is 57.

    What would cause the higher reading?

    Test giver said it measures incomplete combustion.

    At 25 mph, the max is 33, and it measured 7.
    When a 16 year old (almost 17 year old!) car passes smog, it's reason to be happy!

    Mike will probably be able to shed some light on the high HC reading, but just working it out, HC is hydrocarbons (unburned gas) so maybe the car's running a little rich, or the O2 sensor's not reading quite right.. or the catalysts aren't at 100 percent efficiency anymore (which is probably the most likely).

    But hey, in 4-8 years (depending on your state) you ought to be exempt from smog testing!

    CA excluded, of course...

  3. #3
    Senior Member DonTom's Avatar
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    Quote Originally Posted by pearly8 View Post
    Just had my smog check on '94 Lincoln Mark VIII. It passed.

    All results looked great, except at 15 mph the HC ppm measured 57 and the max allowed is 57.

    What would cause the higher reading?

    Test giver said it measures incomplete combustion.

    At 25 mph, the max is 33, and it measured 7.
    One thing that seems to help is to make sure your car is very warm when you do the smog testing, so the catalytic converter can get up to full operating temperature. Climb up some hills before the smog test and try to have it tested at a place where there's not too much waiting.

    -Don-

  4. #4
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    Quote Originally Posted by pearly8 View Post
    Just had my smog check on '94 Lincoln Mark VIII. It passed.

    All results looked great, except at 15 mph the HC ppm measured 57 and the max allowed is 57.

    What would cause the higher reading?

    Test giver said it measures incomplete combustion.

    At 25 mph, the max is 33, and it measured 7.
    Wow. Those standards are TIGHT! I think that the old federal standards for HC were 220 PPM!

    Times have changed.

    Do they do this by year or somehow else?

  5. #5
    Vulture of The Western World Eric's Avatar
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    Quote Originally Posted by swamprat View Post
    Wow. Those standards are TIGHT! I think that the old federal standards for HC were 220 PPM!

    Times have changed.

    Do they do this by year or somehow else?
    My '76 Trans Am would tilt the machine!

  6. #6
    Specific to your car, I think.

  7. #7
    Thanks.

    I'm in California.

    No test now for 2 years.

  8. #8
    Thanks.

    The car tends to heat up in traffic, so I had him test quickly.

    That might be it.

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