I just got my emissions test done and I passed everything except the NOx test. Limits for NOx here is 4.0 and my results were 4.1950. Any suggestions for getting NOx down?

I don't have a lot of money right now as I'm getting ready to ship out for the Air Force in 2 weeks, so I'm wrapping up all my loose ends here. Funds are really really tight right now and I can't afford much.

I was thinking of blending e85 or running higher octane gas to help, as that's what I'm reading online. What say you?

I have already replaced the catalytic converter with a magnaflow and it has not even 1000 miles on it. I don't think it even has 500 miles on it. I haven't yet replaced spark plugs or wires, so I don't know how those are looking. I did replace the air filter (K&N) along with the catalytic converter.

 

My best guess is the Cat but if you got a new one on I'm not to sure. Maybe a BUMP! To your thread will help.

 

Yeah, maybe a bump wouldn't hurt.

I haven't attempted to work on the truck yet, but I'm going to remove the EGR to see how that looks and I have some oil and a fresh filter sitting in a closet, so maybe an oil change would help. I've been reading about seafoam and it seems like a good start for removing internal carbon buildup to lower temperatures. I'm still wondering about the fuel octane though. I'm coming up on another fillup and this next tank I'm getting it tested. Wondering what I should fill it with.

 

You did not say what truck & eng size you have so ??on my 94 Dakota 3.9 V6 it failed the NOX test with 3 different shops trying all sorts of things and big $$ bills,I finally found a nice Tech that passes it for me each year.If you ever find out what causes it let us know.

 

Dangit. I keep forgetting I don't have my truck's specs in my signature. I have the V6 and it's a 1994. Do you know if the tech that passes you was fudging the numbers or was he using some additive in the tank to help it pass?

I'm just paranoid that I'll bring NOx down by fixing or doing one thing and the other items that I passed on will go up and fail.

 

All I can say is I get a new sticker every year,I don't ask how.I do have a rattle in my cat converter that's quite constant and it was never changed but he initially told me he would hate to change it and find out it did no good so??By the way this is in NY State and this year a vehicle that old does not have to go on the dynomator.Some one once said "An auto Tech is not just good he/she is Price less".

 

NOx is the result of high cylinder head temps. Make sure that your EGR is working properly, the EGR passages aren't clogged with carbon and make sure your coolant is OK. You can also do an upper cylinder head cleaner treatment such as Seafoam.

 

I removed the EGR and all connecting pipes last night and it wasn't too bad. I cleaned what little carbon powder was there and put it back on. I also steam cleaned the head with the water (mist setting) in the vacuum hose and it seems to idle and drive a little better now. I did a quick throttle body cleaning and I'm going to pick up some seafoam this weekend and also fill up with some higher octane gas. Hopefully this will pass me.

Do you guys think wrapping the cat with some heat wraps that it'll keep the cat hotter and thus keep NOx emissions lower?

 

wrapping the cat won't do anything to lower NOx unless the cat was totally dead. If you cleaned out the EGR ports, did some seafoam and run 93 octane (high octane fuel is a slower burning fuel thus it will cause lower combustion chamber temps) and made sure that your EGR is functioning correctly, I don't see why you would fail NOx being that you just barely failed the first time.

You might also try using a fuel additive that is sold in Advance Auto Parts from the Lucas company called Ethanol fuel treatment. It helps keep the ethanol that is already in our fuel from degrading fuel lines, pump, injectors and causing all kinds of driveablity problems.

 

I cleaned the EGR, made sure it wasn't stuck, and I just did a full can of seafoam multiple times through the vacuum line. I did 1/3 a can, drove around a bit, did another 3rd, drove around, and the remaining 3rd is sitting in the engine now overnight.

Tomorrow I'm changing plugs and wires. I had the engine light come on with a code 32, bit it always seems to do that when I run shell's 95 octane v-power stuff. It also smells like gas really bad with the v-power 95 octane stuff. Also, the code only seems to come on when trying to go up the same steep hill over and over again. I've been moving the past few days and have made several trips to drop my stuff off and 3 of the times the light comes on at the exact same point and exact same mileage. Could it be gas related since I'm in such a high altitude and am running the not recommended octane gas?