Newest Automotive Ignition System Tester In-line Ignition Spark Plug Tester Automotive Ignition DetectorUse this ignition spark tester to check the condition of the ignition system at each cylinder without going to expensive mechanics. The spark tester connects between the spark plug and spark plug wire in seconds to troubleshoot dirty spark plug connections, defective points and bad cables or connections. Connects in seconds.Troubleshoot spark plug connections quicklyEasy to useConnects in seconds