High NOx Reading

Just had my '85 Camaro in for it's annual inspection. Failed the emissions test. NOx limit is 2.00gpm & it teste at 2.91gpm. Any suggestions as to what to check or replace first in order to lower the NOX reading?

Reply to
MikeLens
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EGR malfunction (not opening all the way, partially blocked port) or slightly lean condition (carb might need an adjustment, is that thing equipped with CCC or EFI?) both resulting in higher combustion temps leading to increased NOx levels.

Doc

Reply to
"Doc"

Reply to
MikeLens

I just went through this with my 84 MCSS. If you have the carbureted 305, I have the most likely culprit is an inoperative EGR system. (per the factory shop manual). I have the EGR diagnostic flowchart avaialble as a powerpoint slide (or JPEG) that I can send you -- if it would be of any help.

On my monte, it turned out to be a bad EGR solenoid.

regards, Le> Just had my '85 Camaro in for it's annual inspection. Failed the emissions

Reply to
Leon Corley

Yup! I've got the carbureted 305 alright. Any help would be greatly appreciated. If you could email me the jpeg of the flow chart it would really help. Thanks a bunch!

Reply to
MikeLens

EGR would be the first suspect (valve not opening, or insufficient flow due to restricted manifold passages). Other than that, ignition timing should be checked. Could also be a worn out catalytic converter.

Reply to
Robert Hancock

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