ASE Test Prep: Spark Plug Procedures

Spark Plug Procedures (VIDEO)

It’s a good idea to polish up your knowledge of engine ignition systems. This video is sponsored by Autolite.


The ignition system test questions you may encounter during ASE testing can show up on the A1 engine Repair test, the A8 Engine Performance Test and the G1 Auto Maintenance and Light Repair Certification test. With that in mind, it’s a good idea to polish up your knowledge of engine ignition systems! Let’s try this ASE practice test question:

Two Technicians are discussing Spark plug testing procedures. Tech A says that to check for spark by connecting a spark tester to the end of a spark plug wire. Tech B says that a regular spark plug should be connected to the end of a spark plug wire to test for spark. Which tech is correct?

A- Technician A

B- Technician B

C- Both techs

D- Neither tech

The correct answer is A. Tech A only is correct because a spark tester should be used to check for spark and attached to a spark plug wire. The spark tester clip should be attached to the engine and the engine cranked to check for spark at the tester. A spark tester requires at least 25,000 volts to fire, so the ignition system is working if the spark tester fires. Tech B is not correct because a standard gap spark plug only requires 3,000 volts outside of the engine, whereas it may require 10,000 volts or more to fire a spark plug under compression inside the engine.

This video is sponsored by Autolite.

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