Emission Fail: NOx

[shoon]

Just got my car etested.. ran it in test mode the first time and passed, so I decided to do the real thing and it has since been failing e-test!!

hydrocarbons are 3 out of allowed 58
CO2 is 0

NOx is 683 out of allowed 643.. and the first time it was 800 something.

The cats were recently removed and are in good shape. O2's are still original.. have no clue where to start. The car was warmed up ALOT when it failed NOx with 800; and only warmed up by idling for 5-10 mins when it failed with 643.

EGR? CAT's ?

the intake and cylinder head / valves were just de-gunked of carbon and rebuilt.

might give the SPOUT connection a try.. and the gas line antifreeze trick.

anyone else had much success with this problem? I've read alot of mixed opinion about NOx failure in the forum.. just curious what methods get immediate results!

Edit:

Brand new motorcraft plugs and wires, fuel filter, and its an MTX.

 

[fiveliterfixer]

If you have an ATX car, then i would test the EGR valve, and then remove it if it passes and inspect the ports leading into the intake manifold. If it's an MTX car, it sounds like a moderate vacuum leak. That i have experienced, these little buggers tend to use some oil and in so doing they deposit it in a charcoal substrate anywhere you have a dramatic temperature change, like an EGR passage or down in the intake ports where the valves seat to the heads. If you like, i'm always available for tech talk via phone, PM, or when i drop through here.

 

[fitefanSHO]

+1 pull the SPOUT, that should get ya where you need to be....

 

[shoon]

I pulled the SPOUT, let the car warm up and ran it and it passed amazingly. NOx dropped from 683 to 125.

:thankyou: