Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! (3 Viewers)

[2001LC]

Just curious, why 1mm instead of the standard 1.1mm, for this style plug?

It's my understanding. They can use this tighter gap because of the plugs design, which produces a great spark with less voltage.

The larger the gap the more power thats is drawn from the coil. The more power drawn, the hotter the coil gets. It is one reason factory has limit on max gap.

On issue of gap. I've noticed the Japanese made and some USA assembled. Are package with plastic protective sleeve. Those the gap and alignment is almost always spot on. I see more issue with the more common ones USA assembled with cardboard sleeve.

When checking gap. It's supper important, to not put pressure on the electroids. That is why I use a slight less in size feeler gauge than 1mm

Spark plug threads are standardized for diameter and pitch. Do you think they are making their male thread to the minimum size? I have a thread micrometer that reads to 0.01mm but I'd need to check brand new plugs. It would be neccesarry to check more than one type of plug to see if DENSO is using a different tolerance.

IDK. Lets us know what you find out. I can say I've never cared for look of threads on the Denso. Especially the USA assemble

I pulled my coils and plugs tonight, as I'm chasing down a driveline shudder (under acceleration) that I initially suspected was a bad u joint. Coils have about 175k (second complete set I installed 8 years ago, OEM Denso) and appear to still be in acceptable condition. Plugs have less than 50k, 2.5 years on them, Denso SK20r11, ordered from directly from Denso online. Surprised to see a gap of 1.9 mm to 2.2 mm on these plugs. I don't recall checking gap at purchase, and I understand you are not to adjust gap on Iridium plugs. FYI, no CEL has been thrown. All plugs appear to be of 'normal' condition except for out of spec gap. Certainly sounds like this could be the cause of shudder, and recent rough idle- will find out tomorrow with new plugs. Incidentally, I've always 'torqued to feel' on plugs, and these were certainly not loose and not too tight. No anti seize applied. Any thoughts on this large gap, perhaps these aren't genuine Denso?

Update- I just researched my order back in March 2018. I didn't get Denso direct order- seems I had a lapse in judgement and ordered Amazon, but I remember being careful, so much for that. Seems I was duped. I left a review on the counterfeit plugs. Seismic LLC, Greensboro NC in Part Sales on Amazon. They're not far from me(Greensboro NC), so I'll have to stop by and drop off the crap plugs they sold me a couple years back. LOL.

It just took me a month (few plugs removed ea of 3 different times in shop), 4 fuel tanks with 44k, seafoam penetrating oil in spark plug tube (remained in between tanks fuel/44k) and a 3/4 breaker bar to pull a set of plugs. It was unbelievable how much power I put into the 3/4 breaker bar all the way out. Unbelievable I didn't damaged threads or bust a plug. It took near 1 hour per plug on last two, just to turn 1/16 time then back at a time. I really got and arm workout.

I was sure they had anti-seize on the threads. This is not something a Shop would put on. A DIY would, and look for best Deal on plugs.

Interesting, the spark plugs center electrode broke as I tried to check gap of the old plugs. I've never seen that happen before. So brittle I could barely touch.

DIY and Center Electriod breaking. BOOTLEG most likely.

 

[OwnerCS]

Wow... Wally World sells those Toyota filters for around $7! I thought they were cheap enough already.

Thanks for the info and suggestions. Is there a sponsor area where one can easily link to the sponsor's sites?

On the main ribbon link.

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[Porter]

Here's a side by side of new Denso plug (ostensibly 'real' from my inspection, purchased from Advance Auto) and the Chinese fake version I pulled with 45k and 2.5 years of service. That is a 2.0 mm gap on the fake. The new plugs are gapped at a hair under 1.0 mm. Thanks to Paul for his detailed experience in this informative thread. So, the fakes will work, but one day you will be driving and feel what seems to be a driveline problem- it doesn't feel like a failed coil. No CEL, and I suspected Drive Shaft/U-joint problem. Bad plugs all along. PS- on a positive note, Seismic LLC, the vendor who sold me the bad plugs over two years ago just refunded me in full, telling me they no longer sell these- kudos to them. Now to remove my negative review!

 

[OwnerCS]

Here's a side by side of new Denso plug (ostensibly 'real' from my inspection, purchased from Advance Auto) and the Chinese fake version I pulled with 45k and 2.5 years of service. That is a 2.0 mm gap on the fake. The new plugs are gapped at a hair under 1.0 mm. Thanks to Paul for his detailed experience in this informative thread. So, the fakes will work, but one day you will be driving and feel what seems to be a driveline problem- it doesn't feel like a failed coil. No CEL, and I suspected Drive Shaft/U-joint problem. Bad plugs all along. PS- on a positive note, Seismic LLC, the vendor who sold me the bad plugs over two years ago just refunded me in full, telling me they no longer sell these- kudos to them. Now to remove my negative review!

View attachment 2458529

I see a quality lot number that was stamped after manufacture on the real plug on the left. Does the one on the right have that type of control code?

 

[Porter]

Fake reads "Denso Japan KN", New good plug reads " Assembled in the US with foreign content"- there are no lot numbers.

 

[sacman]

I recently replaced the spark plugs on my '03 LX470 and the old plugs look very clean. I'm sure they could do another 40K miles easily but I went ahead as the plugs were bought already and they are fairly cheap ($7 from McGeorge Toyota). All the plugs came out very easily without much torque but I couldn't tell if they had anti-sieze applied or not. I didn't install the new ones with anti-sieze. I also replace the air filter and fuel filter at the same time. The end result was fairly noticeable with a little more responsiveness in throttle but that might also be placebo effect. For those haven't done this, the process is very easy and took me about 1hr from end to end.

 

[94SRUNNER]

Decided to check my plugs today. All of them were loose and took little to no torque to remove. They were Denso SK20R11Japan KN. I don’t recall if I used anti-seize but I know I did not use a torque wrench at install. As the picture shows, the electrode were worn out. Those plugs were installed 06/2017 and have about 38k on them.

Based on the worn electrode I decided to replace them.

The new plugs Denso SK20R11 (3297) “Assembled in the US with foreign content" from Advance Auto. All went in without anti-seize and were torqued to approximately 15ft-lbs.

I’ll be installing a new Mishimoto radiator in the near future, at which time I’ll be checking the torque and installing new valve cover seals and spark plug tube seals as I am getting some oil seeping into the tubes.

poor picture quality

 

[94SRUNNER]

@Porter i am wondering if mine were fakes as yours were?

 

[2001LC]

Fake reads "Denso Japan KN", New good plug reads " Assembled in the US with foreign content"- there are no lot numbers.

I see a quality lot number that was stamped after manufacture on the real plug on the left. Does the one on the right have that type of control code?

I've seen fake look even better than genuine. Every detail. Even box had better looking color and print. But typical something or things give them away.

A set of coils, looked so good. I match to OEM Toyota at the parts counter of Dealership. Was even better wrapped than Toyota Denso. Toyota Dense has USA and Japan made depending on PN# (year of 100 series). They do package differently. But we did find minor difference in coils and packaging. One thing Chinese place a space just to right of numbers/letters before a comma. That's a dead giveaway.

With spark plugs I would find as you said MADE IN USA. Rather than Assembled. But some have that, they're perfect and come with cardboard protector. But now I've found reliable source with plastic protection assembled in USA. Those I look very carefully, even from reliable source (concern of fake returns to store as genuine). Being TT spark plugs. I compared the thickness of center electriod. It's that 0.4mm center electrioid they can't "yet" copy.

Most USA assembled I see come with cardboard protector. I get those from Advanced Auto Parts. But some have come with plastic. protector. I suspect, the cardboard protector, is knocking some, out of alignment during packaging. It's those I find most often need gap correcting and or alignment of ground electrode. I've only seen the bootleg TT with plastic cover. But I've also, only seen, real made in Japan Denso with plastic cover.

My biggest, concern even buying from AAP. Is someone has returned a set, substituted their bootlegs purchase off ebay, etc.

 

[Porter]

@Porter i am wondering if mine were fakes as yours were?

I believe you had the same counterfeit product. Looking at the wear on the electrode, that plug most definitely looks out of spec, and way prematurely. I examined the color of the electrode as an online guide states a yellow/ bronze tint is fake. The new plug appeared silver/gray as it should(but my eyes are not as good as they used to be!).

also, the new plugs from advance auto did come with a clear plastic protector, FWIW.

Incidentally, I’ll be getting some parts from the dealership next week and I’ll add a spark plug to the order

 

[94SRUNNER]

also, the new plugs from advance auto did come with a clear plastic protector, FWIW.

Yes. My Denso’s from Advance had the plastic protectors on all of them.

 

[ScottyS]

I just did my plugs at 102k mi, partially in response to @2001LC 's extensive reporting on this.

- 2 plugs on the driver's side were leaking a little gas (browning of the boot, slight staining of the aluminum around the coil seal)
- all plug threads were slightly rust-colored (gas staining I assume)
- all were at or under 10 ft-lbs to unscrew, the front driver's side plug was hand-loose
- existing dual-tip plugs had the top tip almost worn away in most cases
- I replaced with IK20TT Denso's from AutoZone (in green 4x packs, with plastic protectors)
- I put them in with 180 in-lbs of torque, NO ANTISEIZE, after "snugging" with a regular 3/8" drive ratchet

What an easy plug job! Thanks for the tips on the plastic plug removal. For the driver's rear, I just used a 3"+1.5" extension, then my Snap-on impact swivel and then a 12" extension. Easy. People complaining about this plug job need to try a 1st-gen Xterra plug #6 (dealerships notoriously skip that plug).

 

[NoTempoLimit]

Just changed out my coil boots thanks to Paul's suggestion on this thread. It turned out one boot was torn and a few of the others were browned and showed small cracks when squeezed.

Also the rubber boots on the top of the coils were done. I realized how loose the old ones were when I saw the proper way the new ones fit.

Hopefully this will buy me some more time/miles on my original coils (147k miles). I have one new Denso coil on standby for the inevitable time when a coil fails.

Denso's instructions were not very clear. They read "make sure there is a spring in the boot". That's obviously not where it goes on our application.

I ended up not using the included springs and I saved them with my spare coil. The included springs are likely the same as the ones on the coils. I wasn't sure how to remove and replace them.

I went with the 22 N-m (16.25 lb-ft) torque on my plugs (have come out before, very light anti-sieze used). I'm using a certified torque wrench (USA made Proto).

 

[Mike NXP]

Thanks for the advice, was interesting to hear no anti-sieze suggested based on some findings by @2001LC

I am due for an inspection soon, I get some loud clanking for about 3-4 second when first starting the vehicle. I wonder if some clues can be seen when inspecting plugs, maybe a loose one .

 

[ClassyJalopy]

I'll add my own experience to this. My truck started hesitating under load while I was about 800 miles from home. No codes or misfires!
I decided to check on the plugs and 3 were only finger tight! These plugs were installed less that 20K miles ago!
I bought genuine Denso Iridiums from Autozone and replaced all 8. Didn't have access to a torque wrench.

I have driven the truck about 2000 miles since then and never noticed hesitation or misfires!

 

[Jczajka]

Just checked my #1 spark plugs and it came out with little effort. Some oil on the coil and in the bottom of the spark plugs tube.

The plug itself had oily and black threads, some carbon on the electrodes, but not super gunked up.

Plugs and coils are all genuine Denso from Advance Auto. Plugs are Denso SK20R11. Just over 10k miles since all were installed together.


I haven't checked other plugs yet, but what is the consensus on checking them? Should I tighten them all down to 17-18 lb-ft while in the engine?

OR

Do I pull them all, clean the SP tubes with @2001LC rag on a stick and then clean and the spark plugs with all with a HF spark plugs cleaner, brush, or something similar? Then put the clean plugs back in the engine and torque to the higher than FSM torque of 17-18 lb-ft?

OR

Do I spend the $50-80 on brand new plugs (which seems crazy since the current ones are low miles) and replace all my plugs so I ensure the torque is correct?

 

[2001LC]

New

 

[ClassyJalopy]

Just checked my #1 spark plugs and it came out with little effort. Some oil on the coil and in the bottom of the spark plugs tube.

The plug itself had oily and black threads, some carbon on the electrodes, but not super gunked up.

Plugs and coils are all genuine Denso from Advance Auto. Plugs are Denso SK20R11. Just over 10k miles since all were installed together.


I haven't checked other plugs yet, but what is the consensus on checking them? Should I tighten them all down to 17-18 lb-ft while in the engine?

OR

Do I pull them all, clean the SP tubes with @2001LC rag on a stick and then clean and the spark plugs with all with a HF spark plugs cleaner, brush, or something similar? Then put the clean plugs back in the engine and torque to the higher than FSM torque of 17-18 lb-ft?

OR

Do I spend the $50-80 on brand new plugs (which seems crazy since the current ones are low miles) and replace all my plugs so I ensure the torque is correct?

I had this very issue on a recent trip. The plugs has may be 8k miles on them. I had 3 of 8 loose but I replaced the full set (abt $80). Now I just occasionally check the torque on them

 

[Jczajka]

New

Running over to Advance Auto to pick up the Denso Iridium TT (IK20TT) plugs I ordered. $53.20 out the door aint that bad. Going to clean the tubes and torque these on the higher end and check them again after driving a bit.

Going to bring back my Optima Red top, which has always sucked; doesn't hold a charge for long & drains down super quickly.

 

[2001LC]

When rechecking torque, do not loosen. Loosening and Re-torquing the crush washer will not seal as well IMHO.