How do I check an ignition coil?

An ignition coil has 2 coils, the primary with a wire at either end
and a secondary coil which also has a wire at each end. The secondary has more turns of copper wire and steps up the voltage before feeding it into a radio interference suppressor.
It is the contact breaker points opening that cause thousands of volts to appear at the output of the thick wire. Buy a cheap multi test meter and check for continuity and resistance.
The coil is just 2 coils joined at one end ( the earth end ) Colin Beaver Tech. Eng 2008.

colin beaver
June 2008

Thanks John.

Jim Syron
February 2008

There should be continuity on all of your coil connections - but you'll need a multimeter. With the thin wire (LT wire) and earth, expect a low resistance, between the HT wire (spark plug wire) and the LT wire, expect a much higher resistance.

John
February 2008