The electronic ignition (EI) system produces a
high energy secondary spark. This spark is used
to ignite the compressed air/fuel mixture at
precisely the correct time. This provides optimal
performance, fuel economy, and control of
exhaust emissions. This ignition system uses
one coil for each pair of cylinders. Companion
cylinders are a pair of cylinders that are at top
dead center (TDC) at the same time.
The GM 3.4L V6 electronic ignition system is
responsible for producing and controlling a high
energy secondary spark. This spark is used to
ignite the compressed air/fuel mixture at precisely
the correct time. This provides optimal
performance, fuel economy, and control of
exhaust emissions. This ignition system uses one
coil for each pair of cylinders.
Each pair of cylinders that are at top dead center (TDC) at
the same time are known as companion cylinders. The
cylinder that is at TDC of its compression stroke is called
the event cylinder. The cylinder that is at TDC of its
exhaust stroke is called the waste cylinder. When the
ignition coil is triggered, both companion cylinder spark
plugs fire at the same time, completing a series circuit
This ignition system consists of a separate ignition coil
connected to each spark plug by a short secondary wire.
The driver modules within each coil assembly are
commanded ON/OFF by the powertrain control module
(PCM). The PCM primarily uses engine speed and
position information from the crankshaft and camshaft
position (CMP) sensors to control the sequence, dwell,
and timing of the spark
Vehicle Ignition Systems Explained


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