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California: 1991 Honda Accord SE, A/T

New O2 sensor, ran Seafoam, cleaned egr and ports, Egr function properly, Aftermarket CAT 2yrs old, CAT passed backpressure test and no rattling or smell, cleaned IAVC screen.

NOx levels dropped to low 900′s on pretest after cleaning egr ports. Still a hundred to high

Any ideas? Additives? Tricks to pass?

1991 Accord, A/T

I failed my smog and only have a few days to fix it before my temp tags expires! I am in CA so the smog is tough here.

My NoX emissions were high:
15mph – Max 799 – Actual 1206
25mph – Max 738 – Actual 1211

I was also told my timing was off – High RPM. However I checked my timing which looks right on target as well as the RPM at idle sitting right at 800.

So now I need help to pass Smog ASAP. The Cat is working fine and it has a new O2 sensor. The EGR was replaced with a used one which fixed the CEL code 12 it had before.

The car was warmed up with a 20mile drive, I have cleaned the engine with seafoam, new radiator and fresh coolant.

Any idea how to lower that last few hundred PPM?