How to Test a Spark Plug In One Minute

[@TightWadDIY]

Here are some parts discussed in this video! Spark Plug Removal Tool - amzn.to/2Uviqhq Wire Brush for Cleaning Spark Plugs - amzn.to/2VvrkHX Brake Cleaner - amzn.to/2UmPQhS Multimeter (Cheaper Lower End) - amzn.to/2Z0mF2M Fluke Multimeter (Mid Range) - amzn.to/2YUHa17

[@ashokdevotta3890]

Good information. Did not know how to test a spark plug using a multimeter earlier.

[@charlesdowns1691]

I'm using AC Delco iridium.

[@charlesdowns1691]

I avoid Bosch platinum on American cars.

[@eskivelemmanuel270]

Hello

[@eskivelemmanuel270]

Good

[@pbg0avo]

Don't know if you'll get to see this comment. I would like to thank you for your video. I have been flabbergasted trying to get my multi function strimmer going. I always thought I was good with engines. I had a good spark on my coil according to my tester; although my plug didn't seem so good. I reset the flywheel gap, changed the carburetor and just about tried everything but change the plug. I had two plugs which looked in perfect condition, but after doing your test with my own multi meter they both had a zero reading, but a plug from a different machine had a 5+ ~ a bit of a coincedence the two plugs being duds. A lot of people would have given up and put it into a repair shop; who would have charged well over for a repair. I still need to get a plug and try the machine but it seems my problem (fingers crossed) could be solved thanks to you.

[@TightWadDIY]

I’m glad you were able to get it fixed! Thanks for following along!

[@kevinkilloy7608]

Your video saved me a lot of time. Yamaha Beartracker 250 ran great after carb cleaning and then would not fire 4 days later. I assumed the carb again, cleaned and rebuilt again with new kit. Still not firing. I checked for spark with inline tester and the tester was getting spark. My spark plug was intermittently failing and your video told me how to confirm the plug was shorted. Thank you.

[@TightWadDIY]

I’m glad you figured it out!

[@richardroddenberry2079]

Good video, I have been changing sparkplugs in small engines since I was 12 yrs old. I am 79 now. You answered my many questions about the actual condition of those spark plugs. Your explanation of how to test them is the best I've ever heard. Richard Thank you!

[@TightWadDIY]

You’re welcome.

[@fransmith8992]

do some research. this is not a good method at all. read some of the other replies here where they explain why this is wrong.

[@stephenlotto4364]

No you're thinking of your mom who uses a mule to get plowed

[@stellamatutina3573]

@@stephenlotto4364 🤣🤣🤣🤣

[@MrTrekFanDan]

4 yrs later, and still helping people. Thank you!🖖😎👍

[@TightWadDIY]

Glad to help

[@brenthymer7981]

I've never had a spark plug go bad until today. Fantastic video!!! I was able to determine that one spark plug failed.

[@TightWadDIY]

Thanks! I’m glad it helped!

[@LumberjackPa]

Me too. This was fantastic although I chased everything else for the better part of two days during this time off from work. Oh well it kept off the streets and out trouble.

[@1gerard47]

Swap them.over,easy .

[@23aldeezy]

What made you check?

[@JoeRah-q5t]

Most informative video I've ever watched on how to test something. Voice tone and cadence make it very easy to digest info. Well done ol chap!

[@TightWadDIY]

Thank you!

[@joeldavidov2484]

the best explanation and detailed I have ever seen on KZbin

[@johnevatt518]

Great video. Very informative. I used to test spark plug wires by grabbing a hold of them. After getting shocked I sure learned my lesson. Always wear a helmet in case you bang your Head on the hood

[@muwangaherman3832]

😅😅😅

[@嶋田佳子-f5f]

Sorry to say but,,,, the test is incomplete but fun to play with a multimeter. Think of your spark plug like the canary in a coal mine. It will let you know how things are going inside. Garden equipment is notorious for fouling from dirty oil and plugged air box and OLD ETHANOL GAS. add sea foam conditioner to stabilize your fuel . SO, look closely to the tip of the plug where it sparks. A black tip can be from no air flow causing a rich condition or too much fuel or lean is pure white from a vacuum leak likely a hose or carb is loose. Wet is not ...working at all or very little so ideally you want to see off white to very light grey. Oil fouling is obvious from the blue smoke if it runs. If the insulator is cracked and an issue it will back fire or misfire especially under a load . Visually you will see a crack line and feel a crack and see that carbon is in the crack from the arching to ground. USE YOUR MULTIMETER to test the resistance of your leads or plug wires too, if you don’t your test is incomplete. If it misfires under load the wire could be cracked and will be grounding under load. ZAP ZAP ! Take a good look by flexing the wire to open a crack. It will also have a carbon build up from arching to ground. Do a little brake stand in a vehicle or engage the drive on a mower to put a load on the engine warmed up no more than 30 seconds or you will damage your trans. If you have this condition do plugs first, then move on if it is still there and seek a pro for a second opinion. The helmet is a great idea especially if you are standing on wet ground or better yet leaning on a chrome wheel trim in your boxers if you are bare handing a wire. As a friend or neighbor to hold it while you crank it over. Clean some plugs on a small block 100k beauty or stant 6 sure, not a modern car please. The electrode tip where it makes a spark was much bigger, now smaller and fancy metal so it self cleans. Wire brushing or wire wheeling will scratch the porcelain and weaken it . It will look cleaner but won’t last very long like say 20 thousand miles stuff. So, leaving your oil change too long way past 50 % , which also means only 50% of your oil is kind of healthy right ? NO , NOPE , NOT AT ALL, HOT DIRTY OIL , ok I made my point, will not have any lubrications so you can feel it in your fingers. Off of your dipstick feel it compared to fresh. Like your toothpaste the grit is fine. Unlike toothpaste it has to work when it is so hot it will start to smoke dirty oil smokes inside and then stuff happens because it won’t lube the metal to metal anymore so bye bye timing gears and chain on your double overhead variable valve aluminum machine. Please remember what you promised to your mom to wear your helmet.🤠

[@Big_John_C]

Do you piss on an electric fence to see if it's working too? 😅😅😅😅😅😅😅😅😅

[@iyokeobinna2363]

@@嶋田佳子-f5f Wow, let's do business, are you in?

[@adamissah452]

😂😂sorry bro

[@christianperspective9527]

How to test spark plug resistance in one minute. There are several other factors that can affect spark plug failure even though the resistance may be good The insulator may be cracked the spark plug may be fouled or worn out. Check the ceramic insulator on the inside of the spark plug with a light and a magnifying glass. Look for carbon tracking leading from the electrode along the insulator to the body. The shape of the electrode should have a squared edge on the end of it, as the spark plug wears the end of the electrode becomes rounded. A squared edge give a much better cleaner spark than a rounded edge. Also check the insulator on the inside of the spark plug for wetness or oil fouling as these things may provide a path for the spark to bypass the insulator. Last but not least the gap is important. Also the shape of the grounding tab that you bend for the gap this can also be rounded or thinned out on a well worn spark plug. Dont bend it back and forth more than necessary to simply set the gap, you dont want that thing falling off inside the engine

[@prestongodsey3567]

I'm gonna disagree on the square edge gives a better spark. If that is correct, then about every racer from smoky yunick to Richard petty has been wrong. Electricity like air and water, flows easier across rounded edges, square edges cause turbulence and hot spots, which are both bad.

[@christianperspective9527]

@@prestongodsey3567 when you buy a new spark plug the electrode has a nice sharp square edge on it, never heard of rounding the electrode off on purpose. I'm not so sure what Richard Petty does to his race car spark plugs but I know he doesnt enter any race with a lawnmower engine.

[@prestongodsey3567]

Power secrets by smoky yunick. There is an entry about preparing spark plugs. Also 20yrs of n2o foxbody mustangs + 35yrs of 2stroke bikes and quads has taught me plenty about plugs

[@prestongodsey3567]

Most often I can tell what fuel and how much of a spray is being used by looking at the plugs. They say 10k hrs to be a master, I'm a grand master of plugs at this point

[@prestongodsey3567]

Sadly EV's are making that knowledge redundant at an extremely quick pace.

[@paulmueller9065]

Just because the plug passes a resistance test does not mean that it will fire correctly under combustion. Fouled plugs can cause shorting through the insulator at the firing end without you knowing unless you have a special plug tester/ cleaner. These testers were used many decades ago before mechanics realized it was a waste of time. Just buy a new plug and correct the fouling problem.

[@frankdavidson9675]

i am 88 yrs old worked on engs a long time can not remember last i bought a new plug i just blast old dirty oily plugs to restore like new ( small blaster harbor freught sells works very good at 100 psi with fine media then rinse in a little gas to remove any media laying around the post------- i read this carbon path only on highest ohm scale try it next time

[@manolomanoki9915]

Yeah ser thats the problem with "mechanics" that only know to change things

[@paulmueller9065]

@@manolomanoki9915 Our intelligence is revealed by the reasoning of our statements and spelling correctness or lack of.

[@a1nelson]

Absolutely agree. No doubt this technique will find _some_ failures, but I’ve had a couple cases were the plugs will only fail hot. A mechanic friend of mine confirmed that this is not all that uncommon. Presumably, there can be some internal fractures that somehow open up - perhaps by being pulled apart by the expanding steel on the ends. Regardless, this test would be useless on them. Even in this economy, the hit to the wallet by a new plug is much preferred over a headache from a dodgy one.

[@a1nelson]

@@frankdavidson9675 I usually hit fouled plugs with a bit of brake cleaner and a wire bush. A blaster does sound like an effective plan, if you have one available.

[@alcamerc9923]

Here’s something new. I didn’t know people test spark plugs anymore. I haven’t been in an engine compartment in decades let alone know where the spark plugs are, this from a guy who used to be a shade tree mechanic back in the day in Florida. It is good to know that this technology is still available. Good video.

[@babelonchabalala1690]

Great video for ruling out the plug itself ..... Although your multimeter leads are insert wrongly lol..... Black goes into the COM port ..... But in a resistance or continuity test it doesnt matter..... But in a current test it does

[@JustMe-mv6pt]

😂

[@rajaibrar5256]

Comprehensive,short,smart,simple briefing ,thanks

[@graemebagnall6194]

Great video, thanks. Nice and clear. My good old dad taught me a lot about stuff, but not that! And I now know yes, my lawnmower’s spark plug is indeed bust!

[@TightWadDIY]

Thanks! Glad you had a good dad too!

[@andriesviljoen4309]

Thanks for this very useful info. At the VW workshop, we had a spark plug tester back in the day where we tested ALL spark plugs, weather old or new. Now you gave me another way to test them....thanks a million☝️🙏

[@maharaj87]

@Andries Viljoen my mk1 is burning a lot more fuel then it used to, any ideas what could be the cause(injected 1.6)

[@kenwittlief255]

@@maharaj87 your O2 sensor has failed, telling the ECM to inject more fuel than it needs or a temp sensor is telling the ECM the engine is at -90°C

[@drchan5893]

great video sir, this video is very helpful. My generator would not start it only backfires so i thought the engine has spark if it's backfiring but upon testing the plug as you showed, sure enough, the plug was faulty. you saved me from buying a new Generator. thankyou.

[@TightWadDIY]

Great! I’m glad it worked for you!

[@idaniamairena4191]

This spark plug kzbin.infoUgkx-6W-PtUzBRTmACHywsECak2ToY2OpjxN is a quality made replacement for the old Briggs and Stratton 799876 which has been discontinued. This plug fits most Briggs and Stratton 625 engines made since 2011. Most of these engines also have the air gap set to .020, but it is highly recommended to check in your user manual for actual application.

[@spencerakashaggy5599]

I have never known to be able to test a plug , very informative.👍🏼

[@murraymachado401]

Any piece of metal with two ends, you're simply testing the integrity of the metal ore causing electrical "Resistance." A single wire strand 10 inches long, touch tester leads to each end (doesn't matter) of the wire strand in OHMS Measuring on your multimeter tool.

[@timhancock6626]

In the motorcycle workshop I worked in we had a machine that could supposedly test plugs. You could watch a plug on test sparking away merrily on the rig, yet back in the bike the misfire returned until we put a new set of NGKs in, and in many cases it was problem solved. We didn't have the time to sit and wonder why. You just go with what works when your pay packet depends on it.

[@scorpio7five]

@@timhancock6626 but one should know how it works.

[@user-wt8jp4qx6l]

Great video. Just want to add something from my own experience. I had a petrol lawn mower that started great and ran for 5 mins, then died. Did this everytime, time after time. Once it had cooled enough for me to check, the spark plug appeared fine. - sparked strong, no carbon, etc. So I spent hours checking the carb and fuel lines thinking the problem must be there. Last shot, I decided to order and put in a new spark plug anyway. Problem sorted! So, a cold/cool spark plug may test as fine, but the same plug when warmer, or hotter (metal expands!), may be faulty. You live and learn :D

[@TightWadDIY]

Interesting. I’ve never heard of that happening.

[@stephencrouse6032]

Not only can that happen on the plug but other ignition components such as the windings in a magneto.

[@Spitfireseven]

This is the only video I've seen testing spark plugs. It was worth it!!!

[@TightWadDIY]

Thanks! Glad you liked it!

[@thephilpott2194]

Note that this test may identify a 'plug that needs replacing, but it cannot identify a 'plug that is fit for further service. The reason for this lies within ordinary multimeters, which will typically be applying perhaps 6 to 8 volts during the test. A spark plug operates at a pressure somewhere between 8 and 11 atmospheres, and is fed many thousands of volts. A crack in the porcelain insulator will not allow undesirable current leakage from positive to negative electrodes until the 'plug sees this high operating voltage.....which this meter is not able to supply. A failed suppression resistor within the body of the 'plug can however be isolated by this test. Unfortunately there is no substitute for a dedicated spark plug testing machine, (try finding a garage that has one of these now!) and the charge for using this would cut into your budget for buying a new 'plug...so it's not worth it unless the 'plug is rare or very expensive. Not a great idea to clean 'plugs with a wire brush, steel from the brush can potentially deposit onto the porcelain insulator tip and set up unwanted conduction of electricity. Sorry to be so negative!

[@libertyfox7486]

Good info, but air blow after wire cleaning is always best

[@frankdavidson9675]

i use a tiny blaster from harbor freight works like majic that is the only to clean the carbon from porcelain that is pathof least res. wire brush will not go down in there ir rinse after blasting just like new plug when i finish

[@kareno8634]

Thanks! even tho i may not totally understand. - all info seen & read here, can't HtURT. : } TRUTH may HtURT sometimes, but LIES Always do. TRUTH Has Value some refuse to Invest.

[@fransmith8992]

you are 100% correct. this guy is giving bad advice. he does not know what is wrong with what he is doing.

[@mattsphotos749]

spot on Fran , some people don't know what they don't know ..the test will only find a total failure , proper testing often needs to be done under operating conditions , to find intermittent faults or partial failure his requires an oscilloscope .

[@octaviojimenez9274]

appreciate the thorough explaining of the sparkplug.

[@TightWadDIY]

My pleasure!

[@dt1133]

thank you finally someone who explain it this good.

[@TightWadDIY]

Glad it was helpful!

[@rayshamloo2701]

It was one of the best video in this regard.

[@TightWadDIY]

Thanks!

[@arthurforteza3912]

Why did you not test the entire metal cvr of the busted splug to confirm damage inside, tnx for response nice video?

[@willchamberlain3352]

Probably because they are testing for different problems. The test he performed checks for a bad resistor or other problem with the inner electrode. The other test checks for a conductivity between the inner and outer electrodes which shouldn't exist. Having a bad inner electrode doesn't mean testing the outer electrode will confirm the problem. Once he found the first problem, he stopped.

[@mustafabaktr3502]

Thanks for clear explanation, I have chainsaw, 20 hp mercury outboard machine and also analog multimeter. Now I know what to do.

[@TightWadDIY]

You’re welcome!

[@jameschoiwk5573]

It's a nice video. In my opinion, in order to check whether the spark plug has failed or not, it is necessary to check the insulation resistance between the stud terminal and the shell (ground) in addition to the internal resistance. Insulation resistance is to check whether there are any defects that reduce insulation performance, such as internal cracks or pinholes, and can be measured using a mega-tester. In most cases, carbon deposition in the spark plug firing end is caused by incomplete combustion of fuel injected into the combustion chamber due to misfire caused by various factors other than the spark plug's defects. Please note.

[@TheReal1953]

Well, I learned something! The 'megga-tester'......your regular VOM tester only puts out about 9 volts max. Megga testers can put out up to 1,000 volts. The higher voltage forces insulation resistance problems to show up faster.

[@chrispomphrett4283]

It's Megger.

[@davidturner5418]

I made a bench top spark slug tester from an old CRT TV EHT circuit,

[@nelinho1981]

Make a video 🤠

[@williereynolds5136]

I believe the illustration that you show was excellent keep up the good work

[@TightWadDIY]

Thank you!

[@adamdelarozza1985]

When checking resistance; use the apex of the probe to pierce the metal being measured, 'you don't touch the side as you can ground out the probe like you seem to have, use the tip! Also, setting the meter at the Lowest setting will Not damage the meter when checking components out of circuit, there's no voltage! . I use to check out components on an old analog Simpson Meter, It gives a better sense of current flow, when you can see the meter deflection! With a digital meter the numbers are not as easy to read and easily mis-read.

[@tonyreyes9969]

On German Bosch Spark plugs R0, R1, R5 means Zero resistance, 1000 ohms resistance and 5000 ohms resistance respectively. Spark plugs are best tested using an engine Analyser with Oscilloscope when they are under load, meaning when the engine is running and on different load conditions.

[@woodsie5474]

You must be a mechanic, as I have experience in this also. You are correct. However, few people have such access. He is using the meter most people would have to make a generalized assessment as to the plug being within the range of useful life.

[@nikolaikalashnikov4253]

Sounds like a *_Catch-22_* where you "test under load" while the engine is running, yet you cannot get the engine to start because the *_Spark Plug_* might be bad ? ...Or, do you take the *_spark plug_* out & put it into a known good engine ?

[@keithminchin1817]

The problem with this test shown is that the multi meter will only apply around 6V to the spark plug and does not test the ceramic insulator integrity. The spark plug runs in the kilovolt x 10 range which increases as as load is placed on the engine which is why many ignition faults such as spark breakdown occur under load like driving up a hill. Contaminants on the insulator, carbon deposits wear of the electrode and cracking of the ceramic insulator often cause faults. The best way to observe the real performance of an ignition system is by using an oscilloscope. A Megga (insulation tester) could be used but even that is only testing at around 1.0kv….

[@jacobuszwanenburg1629]

True but people generally do have a multimeter and not a oscilloscope

[@karhukivi]

Agreed, a multimeter cannot test for HV breakdown which is how most sparkplugs fail.

[@frankdavidson9675]

@@karhukivi set your ohmeter on the highest ohm setting if you get a reading tiptop to bottom hook its carbon buildup on the post at bottom of plug you can clean that carbon out by by blasting plug is good as new been doing this for years

[@karhukivi]

@@frankdavidson9675 Thanks!

[@jiyushugi1085]

Gotta use a plug cleaner/tester. They can test the plug's performance under pressure. Any aircraft repair shop has one. Bike shops used to, but most probably don't anymore.

[@geraldoceliodamasiodossant7742]

Thanks for your help, my friend! From Curitiba, Brazil

[@TightWadDIY]

You’re welcome!

[@Jodyrides]

As the electrode gap erodes away, it takes more saturation of the coil for the spark to jump the gap. Don’t bother testing or cleaning or re-gapping old spark plugs. If you’re going to go to the trouble of removing them, put new ones in. I never never never use Champion spark plugs in anything I ever own if I can help it. They do not recover after the first heat cycle to 100% performance..I have experienced it first hand when I roadraced motorcycles.. I won six championships, two time national champion racing motorcycles. Champion gave me boxes of spark plugs free. I tried them, I experienced 300, sometimes 500 RPM loss after the first heat cycle. They are like firecrackers. They’re only good once

[@krusher74]

it a shame a company wastes the world's resources on something not fit for its purpose (not the first time i have heard bad things about champion)

[@5150powder]

That is the biggest load of horse shit ive ever heard. Now just for one minute here come back down to reality for me and have a think about this... If that were true, how would champion still be in business after all these years?

[@GripFreak]

@@5150powder perhaps you need to re-read his comment? You obviously didn't understand what he said. What he stated is 100% correct!

[@5150powder]

@@GripFreak he got a bad batch. Thats all.

[@1gerard47]

Champion were the word ,the main man in plugs Long time ago,NGK.no problem ever,never had a bad one,44 years in the industry, looking back,ring condensers and points were a pain always failing,cbs bounce causing ignition timing problems, connecting a timing light, the strobe would be erratic, old mini's.

[@wisecampmotorcycles8258]

The easiest way to check a spark plug, is have a spare one, and install it. Works every time.

[@TightWadDIY]

😂😂True

[@Ihaveseenthings577]

If you are not familiar in the automotive industry with the Ohms symbol, start preparing to look for another line of work, not even for a weekend warrior....I test my spark plugs by telling my helper to hold it with the cable in the " distributor " while I crank the engine to check for spark, now be sure you can outrun the helper....🙂🤙

[@kmancos]

Oldest trick in the book. Still a good one. The other was to charge a condenser, then toss it to the "new guy" saying "catch!" Yep, he gets 20,000 volts for a fraction of a second. And hates you. Until he pulls the same trick on the next new guy...

[@puduy5509]

😀

[@Ocramriv]

You are amazing !,,there's so much info on all your postings that for sure will keep me busy and repair when problem arises , thank you for you time

[@45auto82]

Pretty cool test! When I was much younger, and still in the military, I only had a motorcycle for transpo and I tried sandblasting my plugs to clean them. It ruined them, altho they came out very clean! I still don’t know why that occurred.

[@TightWadDIY]

You could have damaged the white part.

[@blueplasma5589]

old tester machines use to have a sandblaster cleaner section on the machine but they found that the grit left in the plug would be deposited into the cylinder....

[@uredskivid]

@@blueplasma5589 No grit if ya clean em good

[@craigmonteforte1478]

Thanks it’s a good day whenever you gain a little knowledge ad today I learned something about Spark Plugs I did not know

[@rmax5150]

Had no idea some spark plugs had resistors in them. I'm a idiot, lol! New subscriber due to this video. Thanks for posting this! 😎

[@charlesdowns1691]

It's always good to learn.

[@kb3svj]

I never knew that there were resistors in some plugs. Thanks for the good tutorial.

[@theundergroundlairofthesqu9261]

In most plugs! Finding non-resistor plugs can be a challenge sometimes.

[@stevejohnson1397]

Learn something new every day. Thanks man.

[@tywarren4704]

Excellent tutorial. Clear & concise. Thank you!

[@TightWadDIY]

Glad it was helpful!

[@hormazdirani1431]

Faulty spark plugs were always a bit of a mystery to me, especially since most of them look shiny and new. Now that I know how to test them, it sure will reduce the guesswork and help to separate the fishing anchor from the good ones. 👍

[@TightWadDIY]

This test more shows bad spark plugs than identifies a 100% good one. It can’t stress test the plug.

[@1gerard47]

@@TightWadDIY stress test is when it's under load,a multimeter can't do that.

[@1gerard47]

@@TightWadDIY plug leads the same.

[@Old-Sole]

You cannot test spark plugs with a multimeter!

[@alanjenkins7346]

Didn't know you could test plugs. I would always put plug in spark plug wire ground and hit starter to see how much spark there was. Thank you

[@grahamturner6119]

Is it any good testing something that works on over 1000volts with a 9vòlt multi meter /i don't think so/ how can you do a imsulation break down test with 9volts imposible /not posible joker

[@FantaBH]

Very nice and informative video but You indeed forgot one thing. If porcelain is broken below the metal surface, most likely you will not get any ohm reading but still when the spark plug working, the voltage which produces a spark is very high 10k or more volts, and such voltage will jump to the ground there where is the closest spot. Cracked porcelain inside of spark plug will cause spark jump there not where it should.

[@frankdavidson9675]

kind of far fetched the ground of a spark plug is where the threads are along with hook on the bottom when a plug fails its easyer for current to flow in the carbon to gd that jump a gap so no spark if you clean that dirty plug its good as new can remember last time i bought new plugs been cleaning with blaster for years

[@klausl.2212]

Just genious. I will try this method on the spark plug of my XT500

[@62ejo]

Thxs nice too know......Does this also apply to plugs for a car??

[@TightWadDIY]

I sure does.

[@markmdg6]

Same thing

[@miguelasantiago9543]

Nice video Big Brother. Knowledge is power! Thank you so much!

[@ctbully]

Title should be, "How to test spark plugs in 1 minute, 6 times"

[@Joel-j6j]

Just a tip. Never clean or scrape a spark plug with a metallic instrument like a screw driver. It will leave conductive traces of metal on the insulator and the voltage will have a tendency to carbon arc across the metallic trace instead of jumping the plug gap and firing the cylinder. A blaster with a non metallic abrasive medium is your best bet.

[@icecreamtruckog3667]

Testing a spark plug with dc continuity on low voltage is a test that is not rely testing the plug to the fullest. For instance the insulation might have a crack in it and the spark could be sparking inside the plug and not where it is suppose to, or a false positive test. And a high voltage AC current jumps across where DC can not cross. And checking the gap to be the correct distance is also important.

[@andrewcarter504]

That's not rely testing? Surely it should read that's not really testing!

[@dipling.pitzler7650]

But if the test done like shown and the continuity reads zero then the plug is defective regardless if it would somehow work by bridging over gaps using higher voltages.

[@whittler07]

Very good in explaining everything to understand!

[@TightWadDIY]

Thank you for the kind feedback.

[@nimalperera5454]

Thank you. I learnt something I did not know before. It is truly helpful.

[@jeromebreeding3302]

What would the OHM's be for an automobile plug ?

[@jeffdowning4877]

Your meter is set to the 20K 0hms range, So when you say five ohms for instance, you mean 5k ohms, or 5,000 ohms correct?

[@jfrphoto01]

Yes, and he should refer to the reading correctly. It is 5K (5,000) ohms to 6K (6,000) ohms not 5 to 6 ohms! Most quality meters (and even some that are "budget" meters) will show a "K" (thousand) or "M" (Million) or no indication for the actual reading. 1 ohm (no indicator or the ohms [Omega] symbol), 1K (1,000), 1M (1,000,000 or 1 Mega-ohm).

[@harryrenner3001]

Spark plugs can can have fire when tested outside of the combustion chamber. and can loose fire in the combustion chamber under compression although it's rare. and the tip you referred to is known as the electrode.

[@megastick9324]

I’ve seen it many times. Mostly with champion plugs, even new out of the box. It’ll make you pull you’re hair out chasing an issue when you know you just replaced the plugs.

[@megastick9324]

@@harryharry3193 seriously?

[@androidbox3571]

A low voltage resistance check via a DVM is not adequate, the plug needs to be tested at voltages used in operation, ~ 15KV.

[@leeduncan3000]

Thank You. I wish I had information like this years ago.

[@andrewcarter504]

Wish I had correct grammar.

[@andrewcarter504]

Whished?

[@John-s8s8q]

Thanks so much for showing how to test spark plugs!

[@TightWadDIY]

No problem!

[@wmcomprev]

Just a technicality, you said there was no resistance between the center electrode and the ground (screw in portion). This isn't quite accurate since resistance is the amount of blockage offered to the flow of electricity, you do still have resistance (in fact, a lot of it). It should actually be infinite resistance. Had you said no continuity between the center electrode and ground, I'd agree with you.

[@dforge8917]

Well said ! Now I don't have to . Thanks. :-)

[@frankdavidson9675]

any meter reading on highest ohm setting is bad needs cleaning ----center elec. and gd should be infi.

[@springwill]

Thanks man. Needed a quick refresher. Not getting any spark on an old leaf blower. Hoping it’s a easy spark plug, but it may be more than that. Keep up the good work

[@marinduque-theheartoftheph]

Makes sense 👍 Never thought of this before. Thanks.

[@trumpzilla4193]

Dude thanks for making this video!

[@TightWadDIY]

My pleasure!

[@cunnings309]

You say for the second spark plug "there's no reading so there's no resistance" . In fact, no reading means an infinite resistance ( because no current can pass in the electrode). the higher the number is, the highest the difficulty to current to travel. From an old motorcycle mecanic.

[@chrisbaggesi72]

@@georgeiceman867 and open circuit and a circuit with infinite resistance are the same exact thing . this is a dumb ass video

[@kenwittlief255]

you are right no resistance would read 0.0000 Ω

[@stephensmith60]

I needed this. I dropped a spark plug on the garage floor a while back and I can't get my snow-blower to start. The is a great place to test.

[@TightWadDIY]

If you dropped it you could have messed up the gap or cracked the porcelain. This test won’t check for either issue. Just get a new one.

[@QF2653]

When checking threads to center you should be on the highest scale.

[@tomfull6637]

NB! Under high pressure they fail although they show as functioning in atmospheric pressure (if they have a fine invisible crack = short cut)

[@isaacwhite7411]

must correct you on resistance and continuity,if there's a low reading at the base the threaded part and electrode it means it has high continuity not high resistance .

[@jordanv.8707]

I too must correct him for posting video saying "in under one minute" but has 6:18 of video i didnt even watch it. Probably was entertaining.

[@isaacwhite7411]

yea he screwed the resistance thing up saying there should be no resistance when there should be high resistance .

[@jimmynavarro8056]

Excellent video. Appreciate your thorough explanation.

[@TightWadDIY]

My pleasure!

[@johnnygoins7457]

By George I learned something new today, been working on cars since I was little .that entitles you to a subscribe from me ,well done

[@rajanne2947]

Great Information! By the wat the "resistor" you spoke about is also there in many higher amp car relays too.

[@elecrticityelectronics8591]

The résistance of the spark plug does from 6 kilo ohm to 15 kilo ohm, not 6 to 15 ohms.

[@hun44k56]

3:34

[@citec123x]

Even better, 3:26 **lol**

[@JSuparman]

@@citec123x Even even better, 3:24 - LOL

[@erikandreassen6531]

Great how to check. I've found there are 2 resistor types the good one, they have a solid core, the bad ones have carbon grains in the these are deceptivly nasty as they grains over time break down into smaller pieces and settle. Once this happens it sparks internally slowly destroying the grains and the longer they are used the worse it gets plus you get carbon tracking internally making them "look good" even if the gap is now to big to actually fire. Unless you have something like electronic ignition with similar output to a cars (they just keep ramping up the voltage until it can spark but also making for hard starting even on cars).

[@TightWadDIY]

Thanks.

[@lowandslow3939]

That’s all well and good but you didn’t even mention gapping the plug. Used plugs need to be checked for the proper gap between the electrode and the ground (hook). Even new plugs should be checked and adjusted. For the price of plugs, I always toss the old ones and replace with new when doing an engine service.

[@francisxiao1860]

hit the nail on th head right up.

[@roneditz6173]

Yes, your video was very helpful. so much I gained knowledge from this video.

[@TightWadDIY]

I’m glad you found it helpful.

[@djc4446]

very thorough and informative with good camera view so i could see. Thankyou

[@TightWadDIY]

DJ C444 You are welcome. I’m glad you found it helpful.

[@Lakihastam]

What should be the right number for a healthy and quality spark plug?

[@TightWadDIY]

Depends on the plug.

[@Lakihastam]

@@TightWadDIY no i mean when i chek by multimeter number on the multimeter display?

[@lon602]

Good video. Would've been nice to see a cutaway view of the bad plug to see how it failed.

[@livewire2759]

It's pretty much impossible to get a spark plug apart without destroying it, and therefore destroying evidence of the failure. Even cutting it in half would likely shatter the porcelain and the fragile center electrode.

[@deeeeeeps]

@@livewire2759 Diamond saw.

[@livewire2759]

@@deeeeeeps Do you have a diamond saw? I sure as hell don't. LOL

[@jiyushugi1085]

The definitive test is with a spark plug cleaner/tester. The tester is connected to compressed air. You put the plug in the cleaner opening, push the cleaner button and it sandblasts all carbon buildup from inside the plug. Then you you screw the plug into the compression chamber, turn up the air pressure which mimics compression pressure, and you observe the quality of the spark through a small window. If the spark is breaking down under pressure, it's easy to see. This is important because a plug that will fire under atmospheric pressure may fail under compression pressure. These testers are still widely used in aviation, because airplane plugs are far too expensive to discard every time they get dirty. Been using these machines to clean my car/bike plugs for years. Saves a lot of money!

[@renerodriguez2524]

You actually get max resistance from anode to ground. Not “any resistance”

[@frankdavidson9675]

sorry my meter dont read max it onle reads ohms any reading is bad top post to gd or threads if you esee nothing that is good if you have a carbon path youwill see it on highest scale that what i mean by any res. i dont know how to say it any clearer

[@RickMason-yj7pv]

@@frankdavidson9675 1 blank blank is infinite resistance.

[@michaelwilliams3861]

@@frankdavidson9675 sorry for this late comment, but, I think no “continuity “ would be a better term, 👍

[@frankdavidson9675]

one more time --- a bad test on a spark plug is with 1 clip on top of plug the other conn. to hookon the bttom with your meter on its highest scale on ohms 200.000- 300.000 what ever on an analog meter the needle will show somthing -move off infinity that tells me the plug will miss fire because of the carbon build up on the post at the bottom of the plug if you get no reading that tells me the plug is good --- the only to save that plug with the carbon buildup is the small sand blaster plug cleaner with 90 lps press. it will clean that plug as good as new i use this method often

[@ivanvega2821]

Superb video Sir. Thank you for the knowledge transfer!

[@billbammerlin4666]

I just put the plug on the exhaust manifold while still connected to plug wire and crank the engine if it fires it’s good

[@bobpress1235]

Careful with that Bub, that a good way to get jolted outta yur shorts!

[@walterk1221]

@@bobpress1235 only if you have no clue what you are doing; in which case you aught not be meddling/fiddling with it in the first place.

[@lespaulplayer23]

Just because it sparks doesn't necessarily mean that the spark plug is good. It has to be a strong healthy bluish white spark to be good. I would class an orange spark as a weak spark and might not be strong enough to do the job. I've had this on motorcycles that I have had, the plug sparks but not strong enough 😁👍

[@richardrumplik7023]

Thanks, fast easy to understand and you spoke well any easy to understand what you said!

[@mr.tvandenberg7591]

Very helpful. Answered all my questions. Thank you!

[@TightWadDIY]

I’m glad you found it helpful. Be sure to subscribe!

[@pshivjee108]

Amazing Never thought of that. I always just Used to Replace the Spark Plugs.

[@TightWadDIY]

That works too! Haha.

[@MrOnelegnick]

Wow, much faster ways to test them !

[@Jeff82556]

Thank you very much - a very informative video indeed!!!

[@TightWadDIY]

Glad it was helpful!

[@61riosmichael]

simple and straight to the point. Thank you!

[@erickordonez6039]

Very good instructional video! Thank you so much!

[@TightWadDIY]

You’re welcome.

[@sboy1955]

This is a good video and thanks for making it. However folks need to know that this simple test can detect a bad plug - BUT - most bad plugs can also pass this simple test. So like a lot of reviewers have said below, it’s really not a good way to test spark plugs.

[@fransmith8992]

that's what makes it a bad video.

[@Carey-whut]

I liked your video! I just was curious...I guess I could find out by trying it myself. But, I wish you would have mentioned maybe a "normal" range for a car spark plug as well (vs. lawn equipment, etc)... I guess as long as there is continuity...should I care? 👍

[@TightWadDIY]

Honestly it’s easier to just replace them.

[@Carey-whut]

@@TightWadDIY Thanks for your response. I already changed the spark plugs in my 2007 Honda Accord. Hard to believe NGK's had over 100,000 miles on them OEM... so, I replaced with the SAME kind! 👍

[@GrillThisSmokeThat]

@@Carey-whutNice choice!

[@Daniel-OConnell]

There is a lot more goes wrong with sparkplugs than a faulty resistor. Testing a sparkplug at 20 deg C and a few volts is not a good indication that it is OK at 400+ deg.C and 30,000 Volts. Misfires will destroy a catalytic convertor in a very short time.

[@frankdavidson9675]

pls read my pre . comments to clear up some points of testing frank davidson

[@MoDave82]

What about iridium spark plugs ? Does this procedure work on them as well?

[@TightWadDIY]

Sorry I don’t know.

[@frankdavidson9675]

allow me to shed some light on cleaning and testing spark plugs 99% of the time a plug fails from carbon build up around the center post on the bottom of the plug test it this way set meter on highest ohm scale touch the leads togeather should read zero now connect i lead to top of plug the other lead to the (hook) bottom of plug if you get any reading at all you are reading threw the carbon buildup is the bottom i use a small plug cleaner (sand blasterT harbor freight to clean my plugs like new now after cleaning the dirty plug test again the reading will be gone its just like new i have had this same blaster 5 yrs cain not remember last time i bought a new plug

[@omriroberts137]

I’m sorry but that is total rubbish yes if your plugs are caked with carbon then your mixture is out………plugs wear on the tip simply because 250000 v flowing through

[@frankdavidson9675]

@@omriroberts137 just because you dont know how to read a ohm meter dont miss judge j my test been testing plugs about 70 = yrs has not failed me yet

[@VintageCR]

nice video man, if you'd want to check a spark plug before you put it in said small engine.. this is a great way to check a spark plug on resistance value and whether or not it is still okay to use. i checked my plug right after this vid, and its still a-okay.

[@TightWadDIY]

Great!

[@roberttaylor465]

Great but faulty spark plugs can be fine until under compression, hot or cold in the cylinder, it's far better just to replace them.

[@Isgood2beKing]

Thanks for your time and help, I have 3.0 liters engine ans the 6 spark plugs, iridium give me a reading of 3200 all of them, Are they bad or are ok you say 5 to 15, and now i worry

[@DaIrvMeister]

If you engine turns on at all, they are definitely fine. If you have a misfire, start checking the plug wires and coils

[@DaIrvMeister]

To explain that better, different types and brands will have different readings that are their normal. Does the number on your spark plug start with an R like his did?

[@leomattil7931]

This knowledge was I look ing for but you gave me the answer!

[@harrisonayodi1529]

Short and precise. Great

[@TightWadDIY]

My pleasure!

[@MrFERENGI]

thanks, I have the meter but no idea how to use it.

[@TightWadDIY]

There is a lot to learn about them. I don’t know everything. I learn new features as I need them.