Some tools offerred in our online store may benefit from some guidance. The new tool user guides listed may be viewed at any time and are limited to only those tools offerred online here. Always perform very safe shop practices. View: >>>>
With engine turned off and vehicle's park brake applied, disconnect one plug wire from one spark plug. Carefully twisting and pulling the boot as apposed to the spark plug wire may prevent costly plug wire and terminal damages.
Insert the solid brass probe of the spark plug test tool into the spark plug wire end that connects to the spark plug that was just disconnected in the previous step. Connect test tool's thin black wire lead with alligator clamp to a clean engine ground completing the secondary ignitions voltage circuit.
Screw out the ignition spark plug test tool's threaded adjusting knob so that the pointed tip on the threaded screw lines up with number 40 on the spark tester graduation scale. That distance between the pointed tip and the base of the spark tester represents a gap that requires 40,000 volts to jump which is what most vehicles produce for ignition voltage today. Ignition systems working well produce a crisp blue spark measuring approx 40,000 V.
Now idle the engine with the park brake applied. Monitor spark tester gap and there should be a clean and constant crisp blue spark arcing the gap in the test tool if cylinder's secondary ignition system is performing well. Turn off the engine, remove test tool from spark plug wire, reconnect the plug wire to the spark plug, and repeat procedures for the remaining spark plugs.
