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1993 Honda Civic. Not VTEC. Failing Hydrocarbons HC even with a new CAT.

Vehicle has failed 3 times at 2 different locations. After first test only changed cat out with old parts car (had new CAT) in back yard. Failed visual inspection at 2nd test. Failed timing and Hydrocarbons dropped from around 189 max 59 to 55 max 49. Timing was good at first shop. Timing not right even after professionaly set at reputable shop for second and third test. Failing only at the 25mph Hydrocarbons and timing. Wondering where I should be looking now? It's been very expensive so far and need to know what to look for before throwing more money at this vehicle. Should I junk it?
Answer:

First off, timing has to be set regardless of the HC results. It does not make sense for two reputable shops to set ignition timing and yet the vehicle still fail the timing inspection at a smog station or test only center. Someone doesn't know how to set timing properly, or the smog station doesn't know how to check timing properly. Either way before you can diagnose the high HC fault you have to ensure ignition timing is set exactly where Honda requires it to be set. Next... HC can be caused by many things. Number 1 is ignition related. Sparkplugs and spark wires are constantly exposed to high temperatures and high voltage. You must ensure your engines ignition system is functioning properly by inspecting all sparkplugs, their wires, distributor, distributor cap, and rotor. If you've inspected the ignition system and found no faults, you want to then look at the other emissions numbers; specifically CO. CO is Carbon Monoxide, it is partially burned fuel. If on your smog test result you see CO is high, this is an indication of a rich misfire. You want to then diagnose the fuel feedback system. If CO is too low, this is an indication of a lean misfire, and you need to look into the fuel feedback system, as well as any problem which may restrict fuel flow. posted by SmogTips Support

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