HC stands for Hydrocarbon, basicly raw fuel. HC levels so high indicate there is trouble in the combustion chambers... fuel is not being burned properly. The fault can be compression related, ignition related (such as defective timing, sparkplugs, wires, so on...), and/or air/fuel ratio related. We can only recommend having a smog check repair station start by conduct an ignition system test, followed by a compression test, and then a fuel feedback test.
posted by SmogTips Support
