Expert: Mike Evans - 3/19/2010

Question
What was the last year chevrolet engines came with an exernal ignition coil?

Answer
    All gasoline engines have a coil.  All coils are external.  You probably are referring to distributorless ignition.  With DIS there is not just one coil serving the distributor, but a number of coils serving the individual spark plugs.  There are two types of DIS.  One is the type that has a separate coil for each plug, such as on the Chevy LS-series V8.  The other uses one coil for each pair of complimentary cylinders, firing at TDC on both the compression and exhaust stroke.  These are sometimes called "wasted spark," since the spark on the exhaust stroke does nothing.  Wasted spark is simpler, though, and requires fewer coils.  2007 was the last year that Chevy still used a distributor on one of its engines, the 4.3 V6.