I have a 90 honda accord that failed a smog test because the NOx levels were to high.The egr valve is working and the ports are clean.Engine Timing is right.Only thing i figure out is the catalytic converter,but since i live in California new one will cost alot of money and don't want to leave anything out before i get a new one.Also 2 years ago it passed without a problem.

 

Welcome in,sorry I can't help we don't have SMOG test in Ga.

 

I just found out that the car was getting a little hot. The fan switch next to the thermostat is bad.

 

welcome to the forum. Before I take my car to get smogged, I was told to change all filters, change oil. It helps.

 

I changed all the filters. Had oil change,new plugs flushed out radiator. A friend checked the egr valve says it's working and ports a good.Timing is ok,Only thing left is catalytic converter. Nox levels did go down, but still high to fail.

 

could definitely be the cat. a trick i learned when going though emissions is to leave your car running while you wait to have it checked so its warmed up. a cold engine uses more fuel which gives higher emissions. there's also a fuel additive they sell at pepboys that supposedly cleans the cat converter and reduces emissions but i personally have no experience with it so i couldn't tell you if it actually works. you mite also want to use some seafoam additive to clean out your engines deposits.