Is there a remedy for High NO ppm?

[moparjim]

I had my 1992 spirit ES 2.5L turbo e-tested yesterday and she failed. Everything was great except for the NO ppm. They were at 924 when the limit is 467. I have no idea where the timing is because the whole is really hard to see without spending 25 minutes taking all of the air cleaner parts off. Other than that it runs quite well. The cat looks recent also. I think high compression and advanced timing causes high NO ppm readings, but there might be more? Any help is appreciated. Thank you

[Gutfeeling]

You mean NOx? Sorry it's been a while since I had my emission course plus there's no testing over here.
I suggest running higher octane (*unleaded of course) and go at it again.

[ibrake]

Cam timing, spark timing, make sure there is no vacuum leaks, ... etc...

[90 shelby]

NOX= cat or EGR so you dont have EGR you will need a CAT

[moparjim]

I thought it was NOx, but the sheet says "NO ppm" as in Parts Per Million I would assume. I unplugged the temp sensor and was able to read the timing. It was at 14-15 degrees... so I set it at 10 right now to be safe because the emission sticker says to set it at 12 degrees. I also ran a can of combustion chamber cleaner through it. She seems to run a bit better now. The cam timing is correct, i checked it when i took the engine out a month ago. I also replaced some vacuum hoses before and made sure the system was to stock setup. It has about 1/4 tank of gas from January in it, but i put another 1/4 tank of premium in it yesterday.

[dirtyglhturbo]

Quote:

Originally Posted by 90 shelby NOX= cat or EGR so you dont have EGR you will need a CAT

i do this crap every day. 90 shelby is 100% correct. egr problem if equipped, prolly not. it needs a converter. btw what was the co content? you have to watch out, if co is borderline, it may go up when the converter is changed and nox is down. pm me if you need advice

[moparjim]

I just got back from the test centre and she passed! just barely, but does it matter? I ended up taking a little bit more timing out to around 8-9, ran crappy for the test, I just put it back after. Test 1 was at 14 degrees, test 2 is at 8-9 degrees after running a can of Motomaster "engine tune up" through vacuum.
40km/h- Limit test1 test2
HCppm 62 29 35
CO% .35 .02 .04
NO ppm 467 924 438

Curb idle- Limit test1 test2
HC ppm 200 25 33
CO% 1 0.0 0.0

Thanks for everyone's comments. Now I just need to get it aligned, tires swapped, get rid of the old car :)

[crazymadbastard]

Oh- I usally let the tank run very low and add a couple cans of "dry gas" and some say remove the air cleaner element.

[Christ]

This is kinda old, but running lean causes high NOx emissions... (also NO, same thing, afaik.)

"Lean" in this case is referring to stoich... if you're leaner than stoich, and all else is OK, there's a good chance you're putting out more than your share of NOx particles.