Car work in progress

Well, now that I've been home for a couple of days; it's time to think about my car again. Prior to being called away to assist the Red Cross my car had failed it's emissions test. No big surprise considering how heavily modified the engine is. The car didn't fail by a huge margin, but HydroCarbons and Carbon Monoxide are both above the acceptible limits (HC GPM = 1.4138 / limit is 1.2; CO GPM = 25.6146 / limit = 20).

The high HC readings indicate unburned or partially burned fuel; High CO is from a too rich fuel mixture. After spending some time with my scan tool I discovered that my air/fuel mixture is still set to 14.7:1, but I've modified so many parts along the intake that the car's computer is having trouble keeping the mixture in line.

I had no problem with emissions in 2003; but my car was much less modified at the time. This afternoon, I am planning to do a bit of work to hopefully reduce HC and CO emissions: return to stock spark plugs at the stock gap; go to a bigger supercharger pulley, return to stock Fuel Pressure Regulator, clean my air filter and replace my 160 degree thermostat with the stock 190 degree unit. I've also got a special tune for the PCM that will reduce ignition timing to stock levels.

It shouldn't take too long; the larger pulley and hotter plugs should reduce cylinder pressure and burn the charge more thoroughally. We shall see -- I hope to get emissions and registration out of the way today. I really want to get to the racetrack on Wednesday 9/14 and racing depends on having current tags (nothing like waiting to the last minute, eh?)

Mitch