Failed Aircare (smog)

[jgranthevagrant]

Just failed aircare (smog) emissions test. Failed on driving test for carbon monoxide and oxides of nitrogen. Any advice on emissions would be welcome.

Some info: Truck is a 1990 22RE. Has 365 000 k. 20+ k on new head, valves, etc.

Plugs, cap, rotor, are new. Checked valves and timing. Both good. No codes.

O2 sensor is about a year old. Cat is a couple of years old. Probably has 50000 k on it.

EGR controller and valve are original.

 

[pappy]

NOx is controlled by the EGR system so make sure it's behaving.

CO could be a cat issue (as would NOx).

Go to this page and scroll down to the Lambda Calculator. It will tell you if you are running rich or lean, which might give you a place to start looking. http://www.smogsite.com/calculators.html.

 

[Fast Eddy]

If you needed a new head and valves your 'new' cat suffered with the old head and valves for 30k miles and could be all gummed up from it.

 

[jgranthevagrant]

Thanks for the replies. Lambda calculator was interesting. Lambda came out at .3775 and air/fuel ratio came out at 5.55. Pretty sure that means the cat is bad. I think it doesn't help that I run the cat through water pretty regularly. I will probably throw on another one this week, and work on the EGR, which is 24 years old.