--- product_id: 68199103 title: "66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red" brand: "calterm" price: "£41.32" currency: GBP in_stock: true reviews_count: 5 category: "Calterm" url: https://www.desertcart.co.uk/products/68199103-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity-green store_origin: GB region: United Kingdom --- # Adjustable sensitivity dial for pinpoint accuracy Durable ABS housing resists oil and shop wear Dual LED indicators for real-time ignition status 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red **Brand:** calterm **Price:** £41.32 **Availability:** ✅ In Stock ## Summary > ⚡ Ignite your diagnostics with precision and confidence! ## Quick Answers - **What is this?** 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red by calterm - **How much does it cost?** £41.32 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/68199103-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity-green) ## Best For - calterm enthusiasts ## Why This Product - Trusted calterm brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Rugged Durability:** High-impact ABS casing stands up to harsh shop environments, ensuring long-lasting reliability. - • **Instant Visual Feedback:** Green LED confirms tester readiness; red LED flashes with each ignition pulse for clear, immediate insights. - • **Universal Compatibility:** Seamlessly tests both DIS and conventional ignition systems without wire piercing or removal. - • **Effortless Troubleshooting:** Quickly identify ignition faults and 'no-start' issues, saving time and avoiding costly repairs. - • **Precision Sensitivity Control:** Exclusive dial isolates specific plug wires, eliminating false signals and boosting diagnostic confidence. ## Overview The Calterm 66331 Tru-Spark Ignition Firing LED Indicator is a professional-grade diagnostic tool featuring an exclusive adjustable sensitivity dial, dual LED indicators for real-time ignition status, and a rugged ABS housing designed for tough shop conditions. Compatible with both DIS and conventional ignition systems, it enables quick, non-invasive testing of spark plug wires to efficiently troubleshoot ignition faults and no-start problems. ## Description Testing equipment can be put to good use ensuring that electrical equipment is properly installed and safe to operate. Faulty installations can be lethal; the condition of electrical installations can be established when contractors use test equipment. Calterm is please to offer an innovative full feature line of test equipment designed to make electrical work faster and safer. Quickly and accurately test DIS and other ignition systems for the presence of secondary voltage without piercing or removing spark plug wires. Great for troubleshooting 'no-starts'. Review: Work very good Review: Great tool ## Features - SENSITIVITY ADJUSTMENT DIAL is a Calterm EXCLUSIVE feature that allows isolation of a specific plug wire and eliminates false signals from wires routed in close proximity. - Green LED indicates that the tester and batteries are operating properly. - Red LED flashes each time voltage is released from the coil through the spark plug wire. - Rugged high impact ABS housing resists oil and endures shop conditions. - Works with DIS and conventional ignition systems. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B000JFHMPC | | Best Sellers Rank | 204,161 in Automotive ( See Top 100 in Automotive ) 110 in Car Ignition Cables | | Brand | Calterm | | Customer Reviews | 4.2 4.2 out of 5 stars (349) | | Date First Available | 7 Oct. 2013 | | Item Weight | 18 g | | Item model number | 66331 | | Manufacturer | Calterm | | Manufacturer part number | 66331 | | Model | 66331 | | Product Dimensions | 5.59 x 14.99 x 3.56 cm; 18 g | ## Product Details - **Brand:** Calterm - **Colour:** Green,Red - **Item dimensions L x W x H:** 5.6 x 15 x 3.6 centimetres - **Power source:** Battery Powered - **Style:** Modern ## Images ![66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Image 1](https://m.media-amazon.com/images/I/71R5oKpSNAL.jpg) ## Questions & Answers **Q: Does clamp on?** A: Hi, no it's not for clamping on, it's for detecting for a spark and so you just touch it on the ht lead **Q: does it work on small engine 4-cycle, 12V** A: Our Service dept use this all the time on small engines. You do have to properly adjust the dial on the unit for small engines. We use as a quick test. **Q: does this actually detect if the plug wire is pulled loose from the plug itself?** A: Probably not, but a good visual inspection should. I use it to narrow down suspect cylinders that have a misfire such as a defective coil or wire. I have also found plugs that arc inside the plug boots. **Q: Will this work on fuel injectors ?** A: No- Just ignitions. Fuel injectors are low voltage. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Review *by A***R on 21 July 2024* Work very good ### ⭐⭐⭐⭐⭐ Review *by H***D on 6 December 2025* Great tool ### ⭐⭐⭐⭐⭐ Review *by D***S on 10 May 2019* Very handy tool. Accurate. Just remember that this is a firing tool, if your engine is not capable of firing ie. Too much fuel. It will not show you the energy coming from the coil. ## Frequently Bought Together - Calterm 66331 Tru-Spark Ignition Firing LED Indicator, Adjustable Sensitivity, Green,Red - Lisle 19380 Spark Tester - allsun Automotive Spark Ignition Tester 6-24V Pen Engine Indicator Spark Plug Car Wires Coils Diagnostic Tool Auto Voltage Cable Detector Small Engine Tools --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/68199103-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity-green](https://www.desertcart.co.uk/products/68199103-66331-tru-spark-ignition-firing-led-indicator-adjustable-sensitivity-green) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-05-22*