Due to the high voltages involved in secondary ignition systems, it is not possible to make measurements by direct connection, attempting to make a direct connection will almost certainly damage the measuring instrument.
The PP178 is a capacitive pickup which simply connects around the insulation of an ignition circuit component such as a plug wire, this avoids the need for direct connection.
The PP178 comes with a shielded 1.8m (6 foot) lead. It is suitable for use with conventional ignition systems and most HEI and DIS systems. Our library of Automotive Waveforms contains example waveforms captured using a Pico automotive oscilloscope and the PP178.
Although ideal for use with a Pico automotive oscilloscope, the PP178 pickup can
also be used with most other makes of oscilloscope provided they have an
waveform invert option.