Accessory guideSpark Plug Tester

This workshop guide covers the spark plug tester as a diagnostic accessory for confirming ignition spark safely on gasoline engines, aimed at DIY motorists and working mechanics who need a reliable go/no-go check before deeper fault finding. It explains the tool's purpose, the main types available and how to choose one for the job at hand, then walks through setup, safe connection, step-by-step use, and interpreting results with worked examples from real diagnostic jobs. By the end you will be able to test spark quality without risking ignition module damage, read the results against known-good behavior, avoid the common mistakes that create false conclusions, and recognise when a fault exceeds the scope of a tester and belongs with a professional.