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JCMack's avatar
JCMack
Explorer
May 05, 2016

help my 8.1 engine will not pass emissions test in canada

had to get an emission test on my 05 mountain aire with the work horse chasis and the 8.1 engine. the tech. said the engine is running way to rich to which i have to agree as the exhaust smells like it is not burning all the fuel efficiently. there are no codes on the computer the air filter is new and the engine seems to run good. I would have expected to see a code if an O2 sensor was bad. Any thoughts as to what I should be looking at to solve this problem as I intend to work on it this weekend before it is retested on Monday, thank you for any suggestions.
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  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    May 05, 2016
    Hook up an OBDII reader and see what the air fuel ratio is. It should read 14.6-14.7 to be in the correct range, when the engine has warmed up.
    Those engines have a habit of burning the rear spark plug wires but that is usually noticed by a misfiring.
    The Tech should have been able to tell you what the problem was or at least an area of concern other than to just say the engine is running rich. In the USA most large auto parts stores will check your OBDII port to see if there are any codes.
    Are you burning an excessive amount of oil?
  • carringb's avatar
    carringb
    Explorer
    May 05, 2016
    How long since the spark plugs were changed? Ratio can still be ok, but it won't burn all the fuel causing high hydrocarbon emissions, if the plugs are worn out, wires are bad, or otherwise isn't getting strong spark. What about other maintenance? Is the air cleaner ok?

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