1991 Acura NSX Long Term Road Test

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1991 Acura NSX: Smog Test Results, Compared

October 25, 2012


When we purchased our 1991 Acura NSX the car received a smog test. As you can see from the results above, it passed with decent marks. And we had the smog performed ourselves.

In California, a used car buyer has two options: (1) have the seller smog it first; or (2) agree mutually and in writing for the buyer to do it. We opted for #2 when we got the car. But now that we're selling it, we chose the more common option #1. That's were we encountered problems. Take the jump for all results...


The first time we took the car in for a smog, it failed rather horribly in hydorcarbon (HC) and nitrous oxide (NO) emissions. Carbon monoxide (CO) was at passing levels.


So we replaced both oxygen sensors, the air intake temperature sensor and tested it again. It failed a second time. There was noticeable improvement in all areas, but not enough to pass.


We replaced the catalytic converters and all fields improved further. Smoking cigarettes are, again, more harmful to your health than taking drags from the NSX exhaust tips. So, anybody interested in buying an NSX? It's 50-state smog legal.

Mike Schmidt, Vehicle Testing Manager @ 58,300 miles

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