I barely passed my emission test today. The state max HC limit is 85 ppm @15mph and 40 @ 25mph but I came at 85 and 47 respectively. This isn't the first time that happened. It happened the same thing 2 years ago too. All my ignition systems are fully tuned up. The wires, spark plugs, pcv valve, fuel filter, rotor, distributor cap, etc... has only 20K on them. The Cat has 10K. I just changed my O2 sensor cuz I thought that was the culprit but it didn't lower HC a slight bit.

My NOx level came in at 191/73 vs the max limit at 695/717. This is telling me my EGR is working fine.

CO was measured at 0.06/0.05 vs the max limit at 0.5/0.47. Which is very low comparing to HC. Something is telling me ignition is f***ed and burning rich. Any ideas of what could be the culprit that is causing an extremely high HC output?

 

oh yeah, when I moved to CA they don't sell 93 octanes gas over here. So I lowered my timing from 15 to 10 BTDC so I could run on 89 octane gas. Could this be the reason? It's only 5 degree differences.

 

Why is this in the 4th gen forum?

 

just wanna test your knowledge, it appears you guy sucks.... all you knew about were mods but nothing related to the engine.

 

When your HC or CO is high, you need to do a basic tune up. You said you changed all those parts recently, try cleaning everything. Run the fuel injecter cleaner. Spary a can of brake cleaner in the TB and some vaccume hoses.