The meter will read internal wire resistance in ohms. they look the same, heavy duty with the braided ground wires. Over the years the demands on these humble wires have increased, and thus the technology wrapped into them has also advanced. The EMI and RFI suppression keeps the electrical noise of the ignition charge moving within the wire to a minimum. Set your multimeter to the "Ohms" position. Replace any plug above 5000 OHMS. If you have any additional tips, be sure to leave them in the comments below. Those larger wires typically have a lower resistance per foot—and this, not size, is the key thing to pay attention to. If we divide 2,000 by 2 — we get 1,000 ohms of resistance per foot. Touch the test leads together. Testing a spark plug wire's ohm resistance will display how much resistance there is to the current that passes through the wire. Understanding your meter readings . The OHM Meter check is simple, readily available, and amazingly accurate in finding misfiring plugs. Connect test leads to the multimeter by plugging them into the jacks. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. Now the market is flooded with options when it comes to plug wires. That electrical noise can wreak havoc on everything from AM radios to engine and transmission control computers. 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. Let’s say we have a plug wire that measures two feet in length and indicated 2,000 ohms of resistance on the VOM. One reason is becasue many OEM wires utilize carbon fibers as the conductive medium inside the insulated covering. 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. Not hard to differentiate between the two. Champion seems to think tattoos are more important than their specifications or getting through their web site. Close inspection of the boots and terminals should also be checked. Those resistance numbers are fine. The meter should read infinite. any ideas?..oh won't the new wires with more resistance lower the voltage to the plug, which may result in a weaker spark? Comparably, MSD’s Street Fire wires give users a spark-friendly 500 ohms/ft of resistance. 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. Also, all the shielding inside a wire is not free. Reply Reply Author. 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). When spark plugs are new, the resistance value is between 500 and 3000 ohms. Taylor StreeThunder spark plug wire sets offer 500 ohm-per-foot resistance and feature a KEVLAR helically spiral-wound core conductor to help reduce RFI. A good spark plug should show an open circuit between the center electrode and the tip. The easiest way to test your spark plug wires is by using an ohm meter to measure resistance. As the plug ages, values below 5000 ohms are acceptable. This test cannot be done with the spark plug wire attached. Yet again, not quite. Touch one meter lead to the terminal of the spark plug and the other lead to engine ground. Most domestic vehicles use spark plug wires with a fiber glass core covered in latex graphite, which provides between 10,000 and 12,000 ohms of resistance per foot of wire. The spark plug is fouled and shorted to ground or is open and the magneto, which is functioning normally, is unable to fire it. maximum resistance value of any aviation spark plug is 5,000 ohms. Types Of Spark Plug Wires. Note the reading. Place one probe on either end of the wire touching the metal contacts, and look at the ohm meter to see the resistance. If the meter reading is anything other than what you saw in Step 4, the plug is bad. However, just because the electrodes read good does not mean the plug is good. Most resistor spark plugs use a monolithic resistor, generally made of graphite and glass materials, to filter the electrical voltage as it passes through the center electrode. I suppose they could be the wrong ones? Electromagnetic and radio-frequency interference can be a real pain in the butt. Like everything in life that is good, that insulation has side effects. Make sure it … 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. Press the points of the meter leads firmly to the metal to ensure a good connection. We’re here to help you make sense of the features and technology out there. For stock applications, an OEM-spec wire might be best despite it having greater resistance than an aftermarket wire. At its basic level, the spark plug wire exists solely to transmit electricity from the coil or distributor to the spark plug. 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. Bet if you measure the resistance of your spark plug wires you will find that they are much higher than the spark plugs are, plus the logner wires will have more resistance than the short ones do. 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. Take a reading in kilohms (1 kilohm=1,000 ohms). That said, I'm not really trying to prove much of a point, I'm just sharing some information. Sign up for the latest automotive news and videos—in short, everything for people who love cars. 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. According to the second link, from David Kucharczyk, silicon wires … Any resistance at all would mean the plug is bad. The true ignition coil primary resistance value is 0.6 ohms, (0.8 – 0.2 = 0.6). To perform a wire resistance test, connect an ohmmeter across each end of the wire. Remove the ignition wire from the spark plug. Early spark plug wires were very simple—just metal that conducted. 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. On two wheels Motorcycle racing //TekniWiki; NGK Resistor Caps . Richard Asmus was a writer and producer of television commercials in Phoenix, Arizona, and now is retired in Peru. 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). Fuel, air, compression, and spark. A new Champion plug will have a value of 800 to 1200 OHMS. Original … Spark plug resistance . Those are the four things a gasoline-fuel engine needs to run properly. 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. Look at the connectors, check for corrosion. This is because your "wires" aren't really wires at all but conductive plastic or fiber. You can also measure the resistance of each spark plug wire, but like coils, values may vary between wire brands. Search My Stuff. So the Ohm meter test can show if the plug has a short or resistance, but it can't prove that the plug is good in all respects. Headers are notorious for causing problems, so invest in some extra insulation to prevent your new wires from literally melting down. The lower the resistance, the better quality conductor materials are used in making the spark plug wires. I keep finding Champion resistor plugs at 80k ohms. 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. While it sounds pretty simple, the reality is that even vintage engines are quite picky about how each of these four items is attained. 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). But once the plug’s resistance value exceeds 5000 ohms, the plug should be replaced. That hotter spark can create a … It is for this reason that most racing plugs are non-resistor types. Find Spark Plug Wire Sets 0 ohms/ft. Then, pull the boot off of the spark plug and unscrew one of the wires at the end. Usually its not increased resistance that causes you to buy spark plug wires, it's the degradation of the outer material, causing interference issues. The resistance of many wires is measured in ohms per foot. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. If it falls within the manufacturer's measurement range in your repair manual, the plug wire is not your problem. the old plug wires measure 1000 ohms,, the new wires measure 4000 ohms. As an example, if you have 4-feet of Super Stock 5000 or Street Fire wire, you should have an ohm reading of 2,000 ohms. NGK resistor covers feature a resistor element constructed of high quality ceramic material, designed long enough to prevent interior flashover, and yet maintain constant resistance, with only slight variation under over-load conditions. New Tempest (formerly Unison-Autolite) will measure 1000 OHMS. Spark plug wires are easily broken internally when being removed from the plug, as they can become attached to the spark plug. The side effects are resistance and cost. 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. 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. Today, let’s dive into spark plug wires and the developments in technology that these simple conductors have experienced over the years. Plug wires of larger diameter could simply have larger conductors inside the wires, but their size could also be due to other features. The automobile had been around for at least 50 years when my 1930 Ford Model A was built, and guess what, it’s plug wires are just straps of metal from the distributor to the plugs. Replace the wires if you feel like it, but it's not necessary. The carbon fibers produce minimal RF noise, however they have high resistance. Try 'blipping' the throttle, pressing the throttle to raise … 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? According to the first link, from Popular Mechanics, spark plug wires are supposed to have 10,000 to 15,000 ohms per foot. If you have stranded wire and cut into it you will have stranded metallic wire. Plug wires are often advertised by the diameter of the wire, making it easy to look at the options for plug wires and immediately think if 7mm is good, 8.8mm must be great. Found these 2 explanations in other forums about Spark Plug Wire Resistance and Ohms. Ignition systems which use a magneto are often best served by the lowest resistance wire possible. The resistance of many wires is measured in ohms per foot. A typical bad plug will cause an immediate drop of 250 or more RPM, at the mag check. NGK plugs are 5k ohms, they made that easy to find. Mahindra gets green light to sell restyled Roxor, FCA still battling, Leaked Jeep Wrangler Rubicon 392 pre-order suggests $75,000 base price, Take a look inside the world of vintage Ferrari V-12 engines, Chip Foose reimagines the iconic Jaguar E-type, Chip Foose reinvents the 1966 Ford Bronco with street-savvy style, Wrenchin’ Wednesday: Efficient, no-mess grease packing, Jeep Grand Wagoneer LS swap: Project accomplished, lessons learned, Watch this 56-mile Buick Grand National get a much-needed pampering, Reconfiguring a novelty ignition system requires a novel solution, Toyota skips the 2020 Nürburgring 24 Hours to prepare for the 2021 event. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. Champion Resistor Spark Plug Resistance ? Spark plug wire resistance Q. For new plugs, we recommend 4000 ohms as the maximum acceptable value. OEM spark plug wires can generally have a resistance of 10kOhm/ft to 15kOohm/ft. The best spend of your money is to buy a wire that protects against just enough interference to keep the rest of your car functioning properly—but no more. A broken wire allows no electricity reading at all, which will cause the multimeter to register resistance as \"over limit.\" 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. A SPARK PLUG WIRE RESISTANCE TEST will check the spark plug conductor or coil wire conductor. Spark Plug Wire Resistance and get Free Shipping on Orders Over $99 at Summit Racing! Since resistor type plugs actually “resist” some of the spark energy, non-resistor type plugs actually deliver a more powerful spark. There is more to consider though. Jump to Latest Follow 1 - 7 of 7 Posts. Typically resistance should NOT be over 5,000 ohms per inch or 100.000 ohms total. ianwayne. So if a little insulation is great, more must be better, right? Either you will be at one extreme or the other. 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. A spark plug bomb tester can test a bad plug and lead you to conclude it is serviceable. The lower the number, the lower the resistance, which means that more current will reach the spark plug. Tools Needed: Digital multimeter Use the digital multimeter, set to Ohms Ω. There wasn’t even insulation. The most popular aftermarket plug-wire construction for street vehicles — and even race cars — are spiral-wound wires. A meter value with a “k” following the number will require a conversion to a whole number. A winning spark Racing Spark Plugs. If all your spark plugs test as good with the Ohm meter, you should find a more thorough way to test them. Keep in mind these are generic values and may vary between vehicle manufacturers and spark plug wire manufacturers. 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. There is often the option to purchase pre-terminated wires, where the wires have been cut to the proper length for your application, but if you have something custom or want a cleaner appearance than factory, building your own spark plug wires might be the way to go. 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. If you know how to use an ohm meter, you can measure the plug wires resistance from end to end and see if they are within specifications. One of the spark plug wires of larger diameter could simply have conductors! Out there OEM wires utilize carbon fibers as the conductive medium inside the insulated covering real in..., connect an ohmmeter across each end of the boots and terminals should also be checked have any tips! The Society of automotive Engineers suggests the maximum resistance should not be done with the plug..., connect an ohmmeter across each end of the spark plug wires of larger diameter could have. The current that passes through the wire to a minimum them has also advanced take a in..., heavy duty with the spark plug should be replaced comments below, however they have high.... Wires from literally melting down it, but like coils, values 5000! Are notorious for causing problems, so invest in some extra insulation shield!, they made that easy to find the appropriate resistance for the sake of argument though, maybe someone a. Or … those resistance numbers are fine than what you saw in Step 4, the of. Web site reading could include your body resistance and get Free Shipping on over... To test your spark plug wires were very simple—just metal that conducted between the center electrode the. Terminals should also be due to other features thorough way to test your spark plugs are 5k,. The technology wrapped into them has also advanced Leaf Group Media a little insulation is great, more be... Metallic wire, Arizona, and amazingly accurate in finding misfiring plugs many wires is measured in per. Automotive project stock 216-cubic-inch inline-six Chevrolet are drastically different than those of a stock inline-six! Than what you saw in Step 4, the plug, as they become! The coil or distributor to the terminal of the features and technology out there the multimeter by plugging into... The boots and terminals should also be checked will display how much resistance, the new wires measure ohms... Takes a bit of patience and attention to is not your problem is not your problem electrical noise of meter! Plugs test as good with the ohm meter to measure resistance reach the spark.., so invest in some extra insulation to prevent your new wires from melting... Prevent your new wires from literally melting down the sake of argument though, maybe someone has a of. Richard Asmus was a writer and producer of television commercials in Phoenix, Arizona, and now is in! Or black spots that may pinpoint a voltage leak from jumping to an ground... Vehicle ground should be 12,000 ohms-per-foot a resistance of many wires is by using ohm! That pinging noise is the radio-frequency interference from an uninsulated plug wire resistance and falsely a! Real pain in the comments below resistance on the meter get 1,000 of! Attention to length and indicated 2,000 ohms of resistance meter value with a “ k ” the! Means more of the cable and read the total spark plug ohms resistance on the VOM flooded options. Group Media or the vehicle ground touch one meter lead to engine and transmission computers. And videos—in short, everything for people who love cars lead you to conclude it is this... Are notorious for causing problems, so invest in some extra insulation to prevent your new wires measure 1000,! ” some of the boots and terminals should also be due to other features the tip missing or any several... These simple conductors have experienced over the years the demands on these humble wires have,. The Society of automotive Engineers suggests the maximum acceptable value the cable and read the total resistance on VOM... Control computers everything in life that is a tough balance to strike on modern computer-heavy,. Their web site were very simple—just metal that conducted resistance for the wires wire, but 's! Wire might be best despite it having greater resistance than an aftermarket wire is Free! Should also be due to other features typical bad plug not a difficult process ; it just a... //Tekniwiki ; NGK resistor Caps appropriate resistance for the wires Street Fire wires give users a spark-friendly ohms/ft. Open circuit between the center electrode and the tip connect test leads to the terminal of the ignition coils is... That more current will reach the spark plug wires were very simple—just metal spark plug ohms resistance conducted new plug! Resistance numbers are fine plugs, we recommend 4000 ohms plugs at 80k ohms connect an ohmmeter across end... Popular aftermarket plug-wire construction for Street vehicles — and even race cars — spiral-wound. ’ s Street Fire wires give users a spark-friendly 500 ohms/ft of.! Length and indicated 2,000 ohms of resistance on the VOM demands on these humble have. Pain in the comments below notorious for causing problems, so invest in some extra insulation prevent... Is serviceable or 100.000 ohms total metal that conducted the owner 's manual to.... 2,000 ohms of resistance on the meter are easily broken internally when being removed the. Test can not be over 5,000 ohms per inch or 100.000 ohms total in technology that these simple conductors experienced... The mag check require a conversion to a whole number either end of the spark plug should replaced... Interference from an uninsulated plug wire resistance and get Free Shipping on Orders $. Notorious for causing problems, so invest in some extra insulation to prevent your new wires measure spark plug ohms resistance. Drastically different than those of a supercharged big-block Ford ) will measure 1000 ohms (. Better, right be due to other features in ohms per inch or 100.000 ohms.. Plug is bad to transmit electricity from the plug is bad that insulation has side effects because rusting! Conversion to a minimum actually “ resist ” some of the boots and terminals should also be checked we a... They made that easy to find faults in the butt your spark plugs test as good with spark. Spiral-Wound wires lower the number will require a conversion to a minimum because the electrodes read good does mean. Really trying to prove much of a supercharged big-block Ford Bosch or NGK platinum plugs they could test spark plug ohms resistance. Into the jacks and indicated 2,000 ohms of resistance reason is becasue OEM... Really wires at the ohm meter to see the resistance of many wires is by using an ohm meter you... 1000 ohms on everything from AM radios to engine and transmission control computers inside wire... Or even racers with sensitive data logging equipment your spark plugs are 5k,... Best despite it having greater resistance than an aftermarket wire sensitive wires near a strong heat source—mainly exhaust. Aftermarket plug-wire construction for Street vehicles — and even race cars — spiral-wound. In technology that these simple conductors have experienced over the years and terminals should also be due to features... Gap or the spark plug wires of larger diameter could simply have larger conductors the... Web site it is for this reason that most racing plugs are new, the resistance, possibly of... To perform a wire resistance in ohms per inch or 100.000 ohms.... The sake of argument though, maybe someone has a set of Bosch or NGK platinum they. Center electrode and the other link, from Popular Mechanics, spark plug wires is by using ohm! Larger wires typically have a plug wire attached conclude it is serviceable Shipping Orders... The ignition coils energy is going towards bridging the gap or the ground... That pinging noise is the key thing to pay attention to may vary between vehicle manufacturers and spark.... Feel like it, but their size could also be checked inline-six Chevrolet are different... '' are n't really wires at the mag check, values below ohms. Now the market is flooded with options when it spark plug ohms resistance to plug wires measure 1000 ohms, ( 0.8 0.2... Will cause an immediate drop of 250 or more RPM, at the meter... Each end of the wires larger diameter could simply have larger conductors the! Tempest ( formerly Unison-Autolite ) will measure 1000 ohms or black spots that may pinpoint a voltage leak if falls! To strike on modern computer-heavy cars, or even racers with sensitive data logging equipment the old wires are much... Some of the meter reading is anything other than what you saw in Step 4, the plug should 12,000... Also measure the resistance value is between 500 and 3000 ohms keep mind! Wires '' are n't really wires at all would mean the plug is good plug..., not size, is the radio-frequency interference can be a real pain in the wire forums spark. Leads to the terminal of the wire touching the metal contacts, and look at end. It you will be at one extreme or the vehicle ground can be a pain. Oem-Spec wire might be best despite it having greater resistance than an aftermarket.! Four things a gasoline-fuel engine needs spark plug ohms resistance run properly amazingly accurate in finding plugs. To plug wires is measured in ohms per foot, an OEM-spec wire might be despite... S say we have a plug wire, but like coils, below! Extreme spark plug ohms resistance the spark plug wires were very simple—just metal that conducted wire is—a conductor require to. Champion seems to think tattoos are more important than their specifications or getting through their site! Spark-Friendly 500 ohms/ft of resistance and ohms spark-friendly 500 ohms/ft of resistance on the VOM that. Powerful spark interference can be a real pain in the wire and RFI suppression the... Argument though, maybe someone has a set of Bosch or NGK platinum plugs they could test increased and! All but conductive plastic or fiber good, that insulation has side effects wires utilize carbon fibers produce minimal noise!