DIY: How to Test Spark Plug Wires

Video tutorial on how to test a spark plug wires. Over time spark plug wires will wear out, causing various engine operation issues such as hard starting, misfires, rough idling, poor performance, poor fuel economy, and improper combustion burn. Spark plug wires normally last to about 100,000 kilometres or 60,000 miles. This may vary between manufacturers and will also depend on what type of environment they’re exposed to. How to Remove a Spark Plug Wire:    • Tech Tip: How to Remove a Spark Plug Wire   Website: http://4diyers.com Patreon:   / 4diyers   Facebook:   / 4diyers   Google Plus: https://plus.google.com/+4DIYers Twitter:   / 4diyers   Instagram:   / 4diyers   Tumblr:   / 4diyers   Pintrest:   / 4diyers   Tools/Supplies Needed: -spark plug wire -multimeter -spray bottle with water -flashlight Procedure: -as a visual inspection you can look at the wires for any cracking, cut, scraped, or burned exterior casing -inspect the boots on both ends for any damage -inspect the terminals for any corrosion or perhaps they are not holding tightly onto their connections -in a darker environment or at night, while the engine is running, you can also inspect for the wires leaking which would be shown by a spark and an audible tick or click -while the engine is running, you can also take a spray bottle and lightly mist water on the wires which will normally make the engine idle rough if there is leakage in the insulation -for copper core wires, the resistance will be 1 to 6500 ohms -for inductive wires the resistance will be 2200 to 8000 ohms per 1 meter or 650 to 2500 ohms per foot -for carbon wires, the resistance is 10000 to 23000 ohms per 1 meter or 3000 to 7000 ohms per foot -keep in mind these are generic values and may vary between between vehicle manufacturers and spark plug wire manufacturers -first I’ll be testing a carbon core wires -start by measuring the length which is about 2 feet, so we are looking for a measurement of 6000 to 14000 ohms -setting the multimeter to the ohms sitting to measure resistance, on the 20k setting which will show us values in the 10,000 range -touch the test probes together to determine the existing resistance in the test leads -then hold one test probe on one terminal, the other probe on the other terminal, this wire show’s 10,000 ohms, which by generic specs is good -moving onto the next wire, again it’s about 2 feet in length, slightly longer than the first one -touching the test probes on the terminals, we are looking at a value of about 13,000 ohms which is becoming at the high end of the generic range -even if the plug wires meet within their specifications, it doesn’t necessarily mean they are still in good condition as the insulation could be failing, terminals are corroded, or perhaps the conductor inside is broken and that would be show up if you were bending the wire while testing it creating and open circuit -testing an almost brand new wire, these were replaced about 5000 kilometres ago -these are an inductive wire instead which has must less resistant than compared to the carbon core wires -this wire is about 2 feet long so we should be expecting about 1300 to 2500 ohms -we are looking at 940 ohms. While this is below the generic range, these are a higher quality wire so the resistance is less, so as mentioned before, check your vehicle’s specifications or the spark plug wire manufacturer specifications Thank you to all those who watch my videos and support my content. Don't forget to subscribe to my channel for future tutorial videos and like my video if you found it helpful. New videos are always being uploaded every week! © 4DIYers 2013 All Rights Reserved No part of this video or any of its contents may be reproduced, copied, modified or adapted, without the prior written consent of the author.