My baby failed

[rlux4]

My 82 failed emissions for the first time.
It passed OK except for the NO (Nox?) At 15 mph allowable is 1191, I'm reading 1284. At 25 mph allowable is 1021, I'm reading 1111. I don't know what causes high NO, or what I need to do to get it lower. Can anyone enlighten me?
Thanks,
Ron

[narfire]

perhaps try a new O2 sensor. The current one might be hooped and then it defalts back to a middle of the road setting...

[rlux4]

Thanks Chris. I suppose it's possible, but I changed it out less than 15K miles ago.
No guarantee, I know.
Ron

[4uall]

Another option is to move to where there are no e tests for cars 25yrs + (Ottawa)

[TX82FIAT]

No, No, that far North. Come to Texas.

[rlux4]

Canada, eh? Too cold for me.
And I've been to Texas, thank you. I joined the navy to "see the world" and the foreign country they sent me to was Corpus Christi, Texas!
Ron

[SLOSpider]

Timing can make a big difference. Your allow +/- degress so advancing it may all that is needed. Is your Vacuum advance on your distributor holding vacuum? Most of the time they are bad .

[kilrwail]

On my old Mazda rally car, when it failed on NOX it was the catalytic converter that had to be replaced. It's hard to test that without biting the bullet though. Good luck!

[rlux4]

Thanks for the responses.
It is the original cat on the car, so that's very possible. And I'll have to try the timing, it's always passed at 10° spot on, but I know things change as the miles add up.
Ron

[SLOSpider]

When smoging cars that are borderline failing it helps to make sure you have fresh oil, good Chevron gas with a bottle of techron ran through it, new spark plugs, timing correct, vacuum advance working, and heat the crap out of the cat meaning run it hard then have the shop smog it as soon as you pull in before it cools back down. It also will amaze me that just turning the AFM or throttle plate screw half a turn will do. I would also check to make sure there are no vacuum leaks with a can of parts cleaner, propane, starting fluid and fix any you find. You can also read up here on high NOX:

http://www.smogtips.com/failed-high-NO- ... -oxide.cfm

[majicwrench]

Hopefullly someone with modern experience will chime in...but
That convertor has got to be HOT to work right, make dang sure it is HOT.
And the EGR system works to contol combustion chamber temp (high temp in combustion chamber = high NO) and so it has to work properly. Open EGR valve with engine idling and it should kill engine. If it does, great. Now rev engine up, does vavle open a bit?? It should open.
O2 sensor not likely culprit.
Retarding timing a couple degrees may help NO as well.
Keith

[rlux4]

Problem solved!
I got a new cat put on and the numbers are amazing; Nox went from the 1100s down to 39! Average is 439 (at 15 mph). At 25 mph the average reading is 250, mine went down to 11.
The guy at the smog shop says the numbers are like a new car.
WooHoo!!!
Ron

[Gunsmith]

You should still move to Florida Ron, Just sayin.....

[rlux4]

Don't you have to be retired (and older than me) to be allowed to move to Florida?
Speaking of which, my father in law just moved from Florida to Georgia.
The old dog got a girlfriend.
Ron

[Exit98]

Don't you have to be retired (and older than me) to be allowed to move to Florida?

No, you can go Ron, but if you're older than 65 ya gotta keep that left blinker on at all times.

Seinfeld calls that an "eventual" left turn.