Questions and Answers

"Gross Polluter" Q. I have a 1977 Ford 6-300 Econoline Van, 65,000 miles on odometer, and it is now classified as "Gross Polluter" because it had extra high readout of the Nox output on the second Smog test. Would you think that one system is the major cause that controls this portion of the smog gases? Thanks a lot. Orion

A. The major influence on Nox emissions is the EGR valve. By introducing recirculated exhaust gas into the combustion chamber it lowers the combustion temperature to reduce the formation of Nox. It's possible that the EGR valve is not working or the passage from the EGR to the intake is clogged.

I don't know what State you live in, but most States make allowences for the year the vehicle was built. It is not reasonable to expect a 1977 vehicle to pass an emission test and comply with 2001 standards.

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