moterhead

My '93 LX failed the annual emission inspection. On high HC. Limit is 220 and it blew 290. My car has an adjustable fuel pressure regulator. On there when I bought it. I've been told to reduce the fuel pressure to reduce HC. Would someone technically sharp educate me on exactly how fuel pressure adjustment affects HC? Originally the pressure was at 30 with the vacuum line on. I cranked it down to 26. Will this have any adverse short term affect on the engine as long as I don't hammer it? More important right now, will it reduce my HC enough to pass?

TIA

AdderMk2

you basically made the car run lean... you should also retard your timing a few degrees

mjr46

too much HC (unburnt fuel basically) meaning it's running to rich.....also make sure you have a decent set of cats on the car and reducing fuel pressure may help but make sure you have no codes in the cars ecmthat may point towards a system that is not operating correctly on the car....run a koeo/koer test just to be sure

moterhead

I have bumped the timing back from 14 to the factory 10.

Cats are brand new.

What's a koeo/koer test?

No check engine light. Car runs fine. 26 mpg on the highway. It's a built motor, so I'm not surprised that it's taking a bit of finagling to get it to pass. Cobra upper & lower intake, Edelbrock heads, E303 cam, BBK equal length shorties, MSD 6AL box. The list goes on and on. Will try it again tomorrow. Supposed to be warmer. I know cool weather makes run a bit richer.

AdderMk2

you could also try running a spark plug that is one heat rage hotter

88Mach1

http://www.troublecodes.net/Ford/

moterhead

After retarding the timing and lowering the fuel pressure, I had the car retested today. It passed easily! The first time the HC was 290 against a 220 standard. THis time it was a 117!