My 1994 22RE pickup failed the CA smog check this year. If anyone knows what might be the problem, would you mind telling me? Thank you for taking the time to read this.

%CO2 MEAS : 13.4 & 13.2
%O2 MEAS : 0.1 & 0.0

HC MAX: 95 & 60
GP: 285 & 235
HC MEAS: 223 & 243

CO MAX: 0.75 & 0.90
GP: 2.05 & 2.20
CO MEAS: 2.44 & 2.78

NO MAX: 552 & 805
GP: 1600 & 1650
NO MEAS: 951 & 756

 

High HC (unburned hydrocarbons) is often caused by incorrect timing, vaccum leaks, faulty air injection (PAIR), faulty converter, low compression or an EFI problem. Spark plugs or other worn ignition components can contribute to this also.

High CO (carbon monoxide) is usually caused by the air/fuel mixture significantly off towards the rich side.

Your NOx is high at low test but passing at high test suggesting the EGR is working. The failure of this could be too much ignition advance or the converter.

A new converter may bring these results down, possibly passing, but that the HC and CO increase from low test to high test are indications of some other underlying problem.

I'd look at ignition timing, check for vaccum leaks and make sure the cold start injector isn't operating when it shouldn't be before going into the other things. A check of the throttle position sensor may be in order and a proper tune up rarely hurts anything.