HYDROCARBONSLISTED ON THE VIR AS

HC• Raw fuel is primarily made up of Hydrocarbons

(HC).• Should be almost completely broken apart by the

combustion process.• If there is a lack of combustion (misfire), some of

the Hydrocarbons pass through unburned and out the tailpipe.

• Variations in the combustion event (imperfect combustion) allow HC’s to pass through unburned.

• Catalytic Converter can only deal with a normal amount of HC’s.

Causes of high HCHigh HC’s are always caused by misfires, but the root cause may be any

of the following:

• Engine integrity issues (lack of compression, lack of vacuum).

• Ignition timing.• Ignition system malfunctions.• Rich misfires (high fuel pressure, regulator and/or

injector leaks).• Lean misfires (low fuel pressure, dirty injector,

vacuum leaks).• Poor fuel vaporization.• Air Injection system malfunction.• Excessive EGR.• Catalytic Converter operation