{"product_id":"calterm-tru-spark-ignition-firing-led-indicator-tester-green-red-adjustable-sensitivity-non-contact","title":"Calterm Tru-Spark Ignition Firing LED Indicator Tester — Green\/Red, Adjustable Sensitivity, Non-Contact","description":"\u003cp\u003e\u003cstrong\u003eThe Calterm 66331 Tru-Spark is a non-intrusive ignition firing indicator that shows secondary voltage pulses with a green power LED and a flashing red firing LED while offering adjustable sensitivity for accurate testing.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eMechanics, technicians and DIYers need fast, reliable ways to verify ignition activity without cutting into spark plug wires. The Calterm Tru-Spark 66331 is a handheld tester built to detect secondary ignition voltage from DIS and conventional systems without piercing insulation. Rugged ABS construction makes it shop-ready while the sensitivity dial helps isolate individual wires in tightly routed harnesses.\u003c\/p\u003e\n\n\u003ch3\u003eHow does the Tru-Spark show that an ignition circuit is firing?\u003c\/h3\u003e\n\u003cp\u003eThe tool uses two LEDs: a steady green LED confirms the tester is powered and batteries are good, while a red LED flashes each time the coil discharges through the spark plug wire. You can watch the red flashes to confirm consistent firing events or intermittent misfires.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRed LED indicates each ignition pulse visually.\u003c\/li\u003e\n  \u003cli\u003eGreen LED confirms tester power and battery condition.\u003c\/li\u003e\n  \u003cli\u003eNon-contact sensing avoids damaging spark plug wires.\u003c\/li\u003e\n  \u003cli\u003eEasy visual feedback for quick bench or roadside diagnostics.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCan the sensitivity be adjusted to prevent false readings?\u003c\/h3\u003e\n\u003cp\u003eYes — Calterm included an exclusive sensitivity adjustment dial so you can tune the detector to the target wire and ignore nearby conductors. This is especially useful on engines where wires run close together or near metal that could cause stray coupling.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSensitivity dial isolates a single plug wire for accurate reading.\u003c\/li\u003e\n  \u003cli\u003eReduces cross-talk from adjacent wires in tight harnesses.\u003c\/li\u003e\n  \u003cli\u003eSimple rotary control accessible on the tester housing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich ignition systems does the 66331 support and how durable is it?\u003c\/h3\u003e\n\u003cp\u003eThe Tru-Spark works with both distributorless ignition systems (DIS) and traditional coil-and-distributor setups, making it versatile across many vehicle types. Its high-impact ABS housing resists oil, grease and the typical wear of a busy workshop so it holds up to everyday use.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatible with DIS and conventional ignition systems.\u003c\/li\u003e\n  \u003cli\u003eHigh-impact ABS case resists oil and shop abuse.\u003c\/li\u003e\n  \u003cli\u003eHandheld and lightweight for portability during field troubleshooting.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow will this tool speed up diagnosis of a no-start or misfire?\u003c\/h3\u003e\n\u003cp\u003eBy showing when and how often a coil fires, the Tru-Spark helps you quickly determine whether ignition energy reaches each plug wire. That lets you narrow the fault to coils, plug wires, spark plugs or other ignition components without time-consuming disassembly.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eQuickly verifies presence or absence of secondary voltage pulses.\u003c\/li\u003e\n  \u003cli\u003eNon-invasive checks reduce the risk of creating new faults.\u003c\/li\u003e\n  \u003cli\u003eSpeeds troubleshooting, cutting down diagnostic time.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The Calterm 66331 Tru-Spark is designed for professional technicians, mobile mechanics and knowledgeable do-it-yourselfers who need a dependable, non-destructive way to confirm ignition pulses. It’s best for anyone working on passenger vehicles, light trucks or small engines that use conventional or DIS ignition systems and who value rugged build quality and adjustable sensitivity for accurate diagnosis.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Do I need to pierce the spark plug wire to use the Tru-Spark?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No, the Tru-Spark detects secondary voltage without piercing insulation, enabling non-invasive testing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Will this work on distributorless ignition systems?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes, it is compatible with both DIS and conventional ignition systems for broad vehicle coverage.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Calterm","offers":[{"title":"Default Title","offer_id":67593745727673,"sku":"B000JFHMPC","price":60.15,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0822\/3765\/3177\/files\/calterm-tru-spark-front-view.jpg?v=1790578066","url":"https:\/\/redleafauto.ca\/products\/calterm-tru-spark-ignition-firing-led-indicator-tester-green-red-adjustable-sensitivity-non-contact","provider":"Redleaf Auto","version":"1.0","type":"link"}