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'88 Honda Accord Failing smog with high NOX

Old 02-19-2015, 06:26 PM
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Default '88 Honda Accord Failing smog with high NOX


I'm sure many of you have seen these threads many times, but being a newbie to the site, I wanted to make sure my questions got seen.

So I recently inherited an '88 Honda Accord LXi that unfortunately hasn't been able to pass smog. 3 years ago it failed smog and the shop installed a new carb float, oxygen sensor, and cat and that managed to make it pass. Well two years later (and less than 300 miles as my Grandma didn't travel very far) it was taken to the same Smog shop and it failed!

The next month it was taken to a different smog shop, and they couldn't believe the numbers were so low from the other shop.

My guess is to just swap out the Cat but I want to make sure I cover all my bases.Any tips and advice would be greatly appreciated! Thank you all in advance.
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Old 02-20-2015, 09:21 PM
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Default Re: '88 Honda Accord Failing smog with high NOX

Let me guess, she drives it to the store and/or church only and never really lets it warm up and/or never really gets on the gas. This can cause carbon buildup, which would lead to high compression, which would lead to high NOX.

Changing out the cat etc. would probably get it to pass but, unless you fix the carbon buildup then it'll keep failing emissions.
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Old 02-21-2015, 03:47 PM
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Default Re: '88 Honda Accord Failing smog with high NOX

You see how the CO and the HC are reading 0 or near 0? That means you're running lean.

Try changing your fuel filter and gapping your spark plugs to 0.025" and see if that helps.
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