Ford offers one that works with the WDS. Unfortunately we can only compare
two cylinders at a time with the adapter. In the Ford COP systems, the PCM
has direct control over each coil and MA Ford believes that reading primary
waveform is not required and that all we really need to know is if primary
current is being switched. (Primary wave form may look like a mirror of
secondary but because of the difference in winding ratio, it is atually
showing some very different information). Anyway, there is much to be
learned from a real time scope sweep which is an uninterrupted trace of
volts over time. Digital scopes have limitations because of their "scan
rates"..... the information is read then processed then displayed in a
continuous rotation allowing many small (very small) gaps in the
information. Still, the most important information is still there....
ionization voltage, spark line voltage and spark duration.
BTW, the Ford method wants us to concentrate on 3 key readings plus (if we
feel a requirement) the coil "stress" test..... basically an insulation
test. Personally, I don't like this particular test since it can lead to
premature coil failure if performed incorrectly.
If we see low ionization voltage and long duration, rich mixtures could be
one of the causes but it is by no means the only possiblility.... the scope
is but one tool in our aresnal.
When the GM Quad 4 was first introduced (wasted spark, almost a COP system),
to hook our scopes up to it, we would unbolt the the top cover and lay it on
it's back on top of the motor. We would install plug wires between the coil
towers and the plugs...... if a wire came off during testing, those things
could pack a real solid punch.