It would be best if you even considered safety more than ever when dealing with AC as … Removing the HT lead, or coil on plug will reveal the base of the spark plug. This is confirmation that the computer coil driver is sending signal to the coil for spark and that the ignition system is working. The spark plug wire resistance is too high. I know there are other more definitive ways to test the wires but I wanted to just do a quick ohm test. Figure 3. It’s supposed to be several thousand ohms, isn’t it? 2. Jump to Latest Follow ... lets call it your "test" wire...replace your #1 wire...start engine, check it...if stumble persists, turn off engine, move the test wire to the next cylinder ... almost to much to hold for a length of time without being burnt. CASE 5: If you got NO spark from the ignition coil sitting on top of the #4 cylinder spark plug. Rewind the rope around the flywheel and turn the lawn mower's ignition switch on. Next, reattach the spark plug wire. Hint: face the sparking end of the tester so you can see it from the driver’s seat. Each foot of a wire should have a resistance of 10,000 to 15,000 ohms. Attaching the sparker. Not just any sparker. Lower values are much better. Coils and Spark Plug Wires Trouble Shooting. An ignition spark tester like OEM 25069 takes the place of a spark plug – is grounded to the engine and can easily show you whether a particular wire or coil is providing spark. Here are five steps that make using a multimeter to test the Voltage of live Wire effortless: Step 1: Safety When dealing with a live wire, or electricity, safety is paramount. Try to remove the spark plugs by hand the ensure the plugs are properly seated. How to remove a spark plug. There are several new technology items, like a COP or coil on plug testers, which use inductive technology to tell that a coil is firing properly without even removing the coil. The battery powered tester is useful for very small ohm values, not large ohm values. The easist way to check for spark is to remove the sparkplug, attach the spark plug wire, hold the threads of the plug up against the motor case and kick the bike over. Each spark plug will have an HT lead, (on older cars) or a coil on plug attached to the top of it. If you see some sparks, your spark plug wires need to be replaced. That antifreeze isn't leaking into the spark plug well. I bought some new spiral core spark plug wires from Summit racing. If a spark jumps from a plug wire to the test light at any point, this is an indication that the insulation has broken down, and the spark plug wire should be replaced. Therefore, in this article, we shall be focusing on how to check … Removing the ignition coil but leaving it connected to its connector. Testing Continuity The ignition coil consists of a single wire wound hundreds of times around a core, and any break that occurs in the wire renders the coil inoperable. I suggest that you check to see that the 1.) You can measure the resistance of the spark plug wires with a digital multimeter to see if they are working properly. How to Use a Multimeter to Test Voltage of Live Wires. If the spark plug wire looks good, the next step is to check for bad connections or bad switches. Use a spark plug wrench to remove the plugs, one at a time, and tag them to identify the cylinder in which they were installed. Step 4 - Measure the Resistance. Make sure the spark plug gap is near the factory specification. Each wire showed either 1 or OL on the ohm meter which means no continuity (open circuit). Plug caps may be cracked, which can cause corrosion or an open circuit. Discussion about the “right” way to check spark plug resistance can go on until the cows come home. Turn the key to ignition on/run (no need to try to start it). If the lamp lights, it is live. A higher resistance indicates bad wiring. If a spark is present, the spark plug is working properly. The plug wire runs from the ignition coil to the plug cap. When having an issue with your car’s ignition coil, you should test the coil using a multimeter in order to determine which one is experiencing the problem. Spark plug wires have become nearly non-existent on many modern vehicles. If no voltage is observed while the additional coils on the system operate, check for bad wiring, or computer. Your next step is to go to: TEST 4: Verifying The Spark Plug Wire Is Not Bad. I recommend the HEI sparker. It's a very easy test, for the majority of vehicles it involves just two steps: 1. To do this successfully, they need to be covered in thick insulation to prevent high voltages jumping off the wire before it reaches the spark plug and a rubber boot at each end. 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