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Just came back from smogcheck and it was passed barely. HC(PPM) max allowed 61 passed w/60, NO(PPM) max allowed 493 passed w/490. Don't know what these numbers mean -anyone cares to explain?. The tech left a note to check egr value/passage. Also, could O2 sensor has any contributions to this?

This is what I found. Could someone confirm whether this is normal on a 95 EGR Passage? I've seen a few videos on yt and can't find anything like it. I thought there should be caps to drill and hammered out.

note: egr valve and the opening as shown here were cleaned couple years ago with carburetor cleaner but didn't know anything about the passage until now.
Thanks


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95 ERG Passage1.jpg
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Lol that’s crazy somebody went to that length to plug those holes. They’re just supposed to be caps like you said. Makes it a pain to clean unless you take the intake manifold off.

Abbreviation for numbers pulled from Wikipedia. “A relatively small part of combustion gas is undesirable, noxious, or toxic substances, such as carbon monoxide (CO) from incomplete combustion, hydrocarbons (properly indicated as CxHy, but typically shown simply as "HC" on emissions-test slips) from unburnt fuel, nitrogen oxides(NOx) from excessive combustion temperatures, and particulate matter (mostly soot).”

Sounds like you’d benefit from a tuneup. Plugs/wires/rotor/cap/O2 sensor if you pull them out and they look gnarly.
 

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Yes, that is normal for those manifolds. I'm not sure why Honda chose to weld some of them and use the brass plugs in others. You can drill through the beads, clean out the ports, and plug them back up, or remove the manifold and go through the runners. The problem with drilling in is that the possibility of dropping aluminum shavings into the runners is high, which would then require removal to clean out. EGR valve failure or port blockage is only going to cause higher NOx emissions, though, unless all but one port are blocked, which would cause a misfire on that cylinder.
 

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Agreed that you will benefit from a tuneup, and O2 sensor as well. I had a similar experience, didnt pass the smog check, dont know what the NOx and HC numbers were, but the tuneup and sensor made me pass, and the fuel economy returned to normal, 26 mpg or more.
 
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