Spark Plug Wire Resistance and get Free Shipping on Orders Over $99 at Summit Racing! Not only did insulation join the features list for plug wires, increasing use of electronics as the decades wore on required the development of EMI and RFI suppression. Keep in mind these are generic values and may vary between vehicle manufacturers and spark plug wire manufacturers. Connect test leads to the multimeter by plugging them into the jacks. A spark plug bomb tester can test a bad plug and lead you to conclude it is serviceable. Headers are notorious for causing problems, so invest in some extra insulation to prevent your new wires from literally melting down. There is more to consider though. My Profile My Preferences My Mates. That pinging noise is the radio-frequency interference from an uninsulated plug wire. Today, let’s dive into spark plug wires and the developments in technology that these simple conductors have experienced over the years. Those larger wires typically have a lower resistance per foot—and this, not size, is the key thing to pay attention to. ianwayne. For stock applications, an OEM-spec wire might be best despite it having greater resistance than an aftermarket wire. A wire with high resistance can be in the 5000 ohms per foot range for especially high-output ignition systems, whereas a low resistance performance wire could easily get double digit ohms per foot. Touch the test leads together. While it sounds pretty simple, the reality is that even vintage engines are quite picky about how each of these four items is attained. If the meter reading is anything other than what you saw in Step 4, the plug is bad. Any resistance at all would mean the plug is bad. To help assure reliable and trouble free operations, Tempest recommends replacing spark plugs in service having a resistance value of more than 5000 ohms (5k ohms) or less than 500 (0.5k ohms). Testing a spark plug wire's ohm resistance will display how much resistance there is to the current that passes through the wire. An Ohm meter, which is part of a multimeter, can only check a spark plug for a short circuit or a breakdown of insulation resistance. Search My Stuff. The resistance of many wires is measured in ohms per foot. This is because your "wires" aren't really wires at all but conductive plastic or fiber. What's New 3 12 24 72. I keep finding Champion resistor plugs at 80k ohms. Then, pull the boot off of the spark plug and unscrew one of the wires at the end. Here is the first: 200 (ohm) 2K (2,000 ohm) 20K (20,000 ohm) 200K (200,000 ohm) 2M (2,000,000 ohm) 20M (20,000,000 ohm) 5.5 on a 20k or 200k scale is 5.5k ohms If you're reading something that is very low resistance, like a light bulb or a piece of wire, select the lowest (200 ohm). maximum resistance value of any aviation spark plug is 5,000 ohms. the old plug wires measure 1000 ohms,, the new wires measure 4000 ohms. That hotter spark can create a more even burn of the fuel/air mixture in the cylinder, and thus, more power output from the engine. If we divide 2,000 by 2 — we get 1,000 ohms of resistance per foot. A good spark plug should show an open circuit between the center electrode and the tip. Also, all the shielding inside a wire is not free. For new plugs, we recommend 4000 ohms as the maximum acceptable value. Whether you are using an auto ranging meter or a manual adjustment meter for testing, the reading may appear similar to this; (example: .826 k). Set your multimeter to the "Ohms" position. Jump to Latest Follow 1 - 7 of 7 Posts. Move the test leads apart. High-temperature-rated boots might be required if you have headers or other routing that puts the sensitive wires near a strong heat source—mainly the exhaust. After founding a small telecommunications engineering corporation and visiting 37 countries, Asmus studied broadcasting at Arizona State University and earned his Master of Fine Arts at Brooklyn College in New York. There wasn’t even insulation. That’s what a spark plug wire is—a conductor. If you have stranded wire and cut into it you will have stranded metallic wire. Simply attach or hold a meter probe on each end of the cable and read the total resistance on the meter. they look the same, heavy duty with the braided ground wires. The EMI and RFI suppression keeps the electrical noise of the ignition charge moving within the wire to a minimum. Take a reading in kilohms (1 kilohm=1,000 ohms). Once you have your wire chosen, you’ll need to connection the distributor cap (or coil, for coil on plug applications) and the spark plugs. Larry : Wrong about what? According to the first link, from Popular Mechanics, spark plug wires are supposed to have 10,000 to 15,000 ohms per foot. These Granatelli Motor Sports spark plug wire sets combine a solid core, which exhibits nearly zero ohms of resistance, with a … It’s not a difficult process; it just takes a bit of patience and attention to detail—like any other automotive project. 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Early spark plug wires were very simple—just metal that conducted. It is for this reason that most racing plugs are non-resistor types. Your reading could include your body resistance and falsely indicate a bad plug. I suppose they could be the wrong ones? Those simple conductors evolved to require insulation to shield the ever-increasing voltage from jumping to an unintended ground rather than through the spark plug. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. Ignition systems which use a magneto are often best served by the lowest resistance wire possible. That hotter spark can create a … A winning spark Racing Spark Plugs. A meter value with a “k” following the number will require a conversion to a whole number. Either you will be at one extreme or the other. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. Understanding your meter readings . A Taylor ThunderVolt plug wire could easily test at around 40 ohms per foot, which means reduced-resistance and more energy applied to the spark plug. Found these 2 explanations in other forums about Spark Plug Wire Resistance and Ohms. For copper core wires, the resistance will be 1 to 6500 ohms, inductive wires the resistance will be 2200 to 8000 ohms per 1 meter or 650 to 2500 ohms per foot and carbon wires, the resistance is 10000 to 23000 ohms per 1 meter or 3000 to 7000 ohms per foot. The resistance of many wires is measured in ohms per foot. The higher voltage of a coil on plug or distributor system can create enough voltage that a slightly higher resistance wire will not greatly affect spark strength, but the relatively lower output of a magneto means using a lower resistance wire is more important to ensure a hot spark from the spark plug. Make sure it … At its basic level, the spark plug wire exists solely to transmit electricity from the coil or distributor to the spark plug. any ideas?..oh won't the new wires with more resistance lower the voltage to the plug, which may result in a weaker spark? Typically resistance should NOT be over 5,000 ohms per inch or 100.000 ohms total. On the other hand, many import models like Nissan, Honda, and Toyota use spiral-wound stainless steel mag wires with approximately 500 ohms of resistance per foot of wire. Testing Plug Wires: If you have access to a factory service manual for your car, you may find a resistance rating for the spark plug wires, (such as 1000 - 4000 ohms per foot). According to the second link, from David Kucharczyk, silicon wires … Replace the wires if you feel like it, but it's not necessary. A typical bad plug will cause an immediate drop of 250 or more RPM, at the mag check. Like everything in life that is good, that insulation has side effects. Spark plug wires are easily broken internally when being removed from the plug, as they can become attached to the spark plug. Yet again, not quite. On two wheels Motorcycle racing //TekniWiki; NGK Resistor Caps . Those resistance numbers are fine. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. Re: Spark Plug Wire Resistance reading I don't know personally, but zero"ish" for stranded wire and 5k ohms"ish" for resistance wire, obviously length dependent. Do not touch the tips of the test leads or the vehicle ground. NGK Spark Plugs for formula one racing quality. It could have the tip missing or any of several other problems. The meter should read infinite. Spark plug resistance . The spark plug is fouled and shorted to ground or is open and the magneto, which is functioning normally, is unable to fire it. Remove the ignition wire from the spark plug. The purpose of the resistance in the plug wires is there so that the (1) plug firing voltage is great enough to maintain a sufficent spark firing time and (2) the resistance suppresses interferance with electronic equipment and radios. One reason is becasue many OEM wires utilize carbon fibers as the conductive medium inside the insulated covering. When one cylinder's spark plug has a resistance value of 4300, and another cylinder's plug having a resistance of 5400, would you think that it really matters? Higher readings indicate too much resistance, possibly because of rusting or faults in the wire. A SPARK PLUG WIRE RESISTANCE TEST will check the spark plug conductor or coil wire conductor. The most common instance of radio frequency is the phenomenon that occurs when a home mechanic replaces the plug wires on a vintage car and afterwards the radio has a pinging noise whenever the driver turns on sweet tunes while the engine is running. Try 'blipping' the throttle, pressing the throttle to raise … A new Champion plug will have a value of 800 to 1200 OHMS. A good spark plug should show an open circuit between the center electrode and the tip. Touch one meter lead to the terminal of the spark plug and the other lead to engine ground. Reply Reply Author. S ... Wire 1: 4.8k Ohms Wire 2: 5.5k Ohms Wire 3: 5.5K Ohms Wire 4: 6.2K Ohms Now, wires 1-2 are the same length, as are 3 and 4. This maximum value is based on the tested values of the plugs that the marketing company sells, and is in no way indicative of the spark plug market in general. The meter should read zero Ohms. Discussion. That electrical noise can wreak havoc on everything from AM radios to engine and transmission control computers. Electromagnetic and radio-frequency interference can be a real pain in the butt. Spark plug resistance. The side effects are resistance and cost. Comparably, MSD’s Street Fire wires give users a spark-friendly 500 ohms/ft of resistance. Sign up for the latest automotive news and videos—in short, everything for people who love cars. Installing new plug wires is a part of most basic tune-up to-do lists, and if your favorite cars wires haven’t been changed in a decade or so it might be time for you to start shopping. As the plug ages, values below 5000 ohms are acceptable. Press the points of the meter leads firmly to the metal to ensure a good connection. I saw one little statement in an aviation forum that they use some sort of silicon carbide voltage dependent resistor and can't be … A wire with high resistance can be in the 5000 ohms per foot range for especially high-output ignition systems, whereas a low resistance performance wire could easily get double digit ohms per foot. Any resistance at all would mean the plug is bad. 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