Fake NGK Iridium Spark Plugs | How To Test!!

In this video I will show you a set of fake NGK Iridium spark plugs that I purchased online. These fake ones look almost identical to the real ones. I will compare them to a set of genuine NGK spark plugs and show you what how to test them.

- With the fake NGK spark plug, the Elantra was getting 22 MPG
- With the real NGK spark plug, the Elantra was getting 25 MPG

** MEASURING RESISTANCE WITH MY HAND ON THE PROBE!!
I know many of you are commenting about me holding the probe when testing the spark plug. There is no problem with the measurement with my finger touching the probe. My body resistance is in parallel with the resistance of the spark plug. My body resistance is in the Mega-ohm range, and the spark plug resistor is 5 kohm. Since my body resistance is much higher than the spark plug, the parallel resistance will always show the lower resistance value (which is 5 kohm). This is not speculation, this is electronics. You can calculate resistance in parallel and the combine resistance of my body and the spark plug is 4.999kohm. This is basic electronics you learn in Electronics 101 class. You can google the formula for calculating resistor in parallel and do the calculation yourself. Or if you want, test it yourself with a 5kohm resistor.

SPARK PLUG RESISTANCE INFORMATION:
Most spark plug manufacturers will put the letter 'R' in the name to designate it as a resistor spark plug. The resistance can vary depending on the design and manufacturer. Often the resistance is between 3 - 7.5kohm. But there are spark plugs that may have lower or higher resistance. Also the reason for adding resistance to a spark plug is to reduce spark ignition noise which can interfere with a car's audio system.

You can read more information on NGK website here:

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Tools:
Auto Ranging Multimeter

Spark Plug Gap Tool

Spark Plug Socket Set

TEKTON 3/8" Adjustable Torque Wrench (10-80 ft-lb)

GEARWRENCH 3/8” Adjustable Torque Wrench (30-250 in-lb)


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[worldsails]

I've watched a lot of videos about fake NGK plugs. You are the first person who actually provides a scientific way to tell the difference.

[wayne]

When measuring resistance don’t touch both leads. Your body creates a parallel path and it will bias your readings. Often it won’t matter but a good practice for when it does.

[johnmashariah]

Measuring the resistance is the best way to differentiate the real and fake plugs, an educating video and clarified.

[sosemann]

Thank you ! I'm from Chile and I've just bought the same spark plugs here . Got my multimeter and ran the same tests and they were fake indeed!!!! Owe you a big one !!! I've just saved my engine from a potential torn up. You Rock!

[davidschlereth]

YOU SAVED ME !!! Came across your video and decided to watch it and scrutinize the NGK’s that I bought on eBay that I was about to install in my BMW 330 CI and to my surprise they are indeed fakes! Went and got a real set from my local auto parts store, cost a little bit more, but they have all the hallmarks of genuine NGK‘s! I can’t thank you enough for this very helpful video. Thank you.

[RailFan-xqhq]

Wow, I had no idea that about fake NGK plugs. My plugs arrived today. I watched this video and ran to the shop for my VOM. 4.57 to 4.73 k. Thanks for helping us all out.

[lancepayne]

Did not know this was a thing!! I just installed new NGK Iridium plugs in my motorcycle, gonna run the test when I get home!!! Thank you!!!!

[ScottoGrotto]

Very good video, and excellent consumer protection/Public Service!
I thought I was saving $ buying sets of 4 NGK iridium plugs on Amazon for ~ $25

My dealer pulled my plugs while diagnosing my cars running issues.

I didn’t have time to order cheap ones, didn’t want to pay dealer markup, so picked up a set at a local parts place.

Car definitely ran better with the locally sourced set.
Started to think that cheap plugs on Amazon were likely knock offs, and you confirmed it!

Thanks 🙏

[tedjohnson]

I was curious about the internal resistor, since I'd never heard about that. Found a really good pic. on the NGK site, which labeled it as a "glass resistor". That helps explain what a veteran mechanic told me, "When you drop a spark plug, always drop it twice". The second time is when you drop it into the garbage can, because it might have an internal or hairline ceramic fracture that will result in premature failure.

[TechTimeWithEric]

I recently bought a high mileage Camry as a project car for my channel. From over 10 years in the automotive aftermarket I knew there were counterfeit parts; but I had no idea how prolific the counterfeit Toyota parts were. Luckily for me, the Toyota dealer was not even $10 more for me than AutoZone with my commercial account for all the plugs and filters for my car. I'm really glad that people are bringing attention to this problem.

[crxtodd]

Good idea to check the resistance, never even thought of doing that.

[modelotime]

we live in a world where i have to worry about fake spark plugs? wtf bro

This vid is SO GOOD that it should be listed under the official NGK channel!

[Grumpy-sywr]

I learned from my own mistake a couple of years ago. Around half price you'd pay elsewhere, set of 4 NGK Iridium from Ebay. 6, 000km, the car went back to running rough, hesitating as before installing the new plugs. This made me assume something else was failing. After new coil, leads and some messing around with no improvement, I pulled the 'new' plugs out, and found the center electrodes burnt down to almost nothing. A set of confirmed genuine plugs later, and I've so far had 30, 000km of trouble free driving.

[adilnabbie]

I was about to buy some ngk from ebay for cheap knew it was too good to be true. Thank you

[russbilzing]

I have had troubles with spark plugs in motorized bike engines. I never thought to measure the resistor impedance. Your answer provides the the consistency values I was missing. Thanks for clearing up this mystery and giving me some way to prevent future errors.

[DZ]

Excellent information. Thank you for bringing it to our attention !

[provemewrong]

Bought some fake ones off of Amazon as well. Installed them on my pathfinder and after a few months read an article about fakes. Ended up inspecting them and sure enough they were fakes. Gaps increase by 50% only after a few thousand miles. Complained to Amazon and they denied my review to be published. Next time I will only buy plugs from a local shop. Good thing I caught this. Thanks for a great video!

[davidwilliamson]

Thank you for putting out this video. I wasn’t aware of the fake NGK spark plugs until I saw a random video on UTube pertaining to that subject. Your video is the only one I have seen that details how to check the resistance with a multimeter. This to me was the determining factor for authentication of the spark plugs as the only thing I had to compare them to was the old ones that I took out of the engine that had 134, 500 miles on them. I chose the safe and most expensive route by buying the spark plugs from my local Auto Zone.

[knowyuhgrow]

Wow thanks for sharing. Over the years I seen so many bad spark right out the box and I’ve realized most customers have been buying them from Canada tire, i didn’t think about fake plugs I just thought bad storage or bad quality control