Tiny ignition coil cracks(?)

2003 V8 access cab, 152K miles, no CEL, but some rough running (or, as my wife thinks, I'm just overly sensitive / paranoid).

I'm trying to find clear info on what determines if an ignition coil needs to be replaced. I've tried searching the forum, didn't readily find cracks like this being addressed.

-Cracks: 6 of my 8 coils have what seem to have, to my inexpert eyes, tiny cracks along the seams. With the caveat that I realize it may be hard to tell from a photo: are these "bad" and need to be replaced?

I don't see any discoloration around the cracks, or any other signs of something wrong. Aside from these tiny cracks the coils are indistinguishable from the two that don't seem to have any such cracks. If I didn't have a new one to compare two I might think these were just seams from the manufacturing process.

-Non-visible internal damage: As far as I know mine are original coils, with 150,000 miles and 20 years of Arizona heat on them. Are these items that should be proactively replaced periodically?

 

I wouldn’t assume the rough running is because of the cracks, but if it does pour outside and your truck runs like crap the following morning, I’d suspect it’s moisture getting inside and creating a resistive short.

 

Others have brought up cracks, but I haven't seen the long side seams cracking.

I think you'd be crazy to proactively replace all of them at once, but if you have the funds, at 20yr/150k, I also think it's small insurance.

You could probably get away with just replacing 4 of the worst. I think it was PHM that tried to sleeve his, maybe, I've seen a couple others try with no luck.

Whatever you do, buy Denso, from parts.toyota.com, RockAuto, Summit Racing, or similar. Don't shop on fleaBay, scAmazon, WalMart online.

 

Oh, interesting. On the rare instances that it is rainy / humid here, it does seem to be a little rougher.

Cool, good to know. I kinda did that: the previous owner had put one random bolt on the #7 cylinder's ignition coil, and it wasn't super tight. That coil looked sketchy, dirty, scratched, etc, so I ordered two Denso coils from RockAuto. Figured I'd replace that one funky one, and have a spare.

As I inspected all 8, I decided to replace the two worst, then ask here if they are actually "bad". If not: backup spares.

May slowly keep replacing them like you said.

(I also got the correct bolt for the ignition coil while I was at it....drove me nuts having to have a 10mm socket for 7 of them, and a 1/4in (or whatever it was) socket for #7.)

PS... where is PHM?? His old posts have a line through his name? I've been busy with new job, haven't been on the forum as much lately, and it seems like he's gone?

 

He and a few others have gotten banned because they can't separate politics from trucks. It wasn't a one-time-offense type thing, there were multiple warnings, a 4-day, a 7-day, I think a 30-day infraction before the final ban. It really genuinely sucks, because a number of folks we lost are great assets otherwise.

There's a definitive split here, with those who need to make things political, which tends to be super divisive, and the rest who just want to talk about trucks, something we all fundamentally agree on. A number of the folks who can't help but inject their politics into things have moved to other forums.

EDIT: We've lost a couple of other awesome dudes like @Darkness and @chrisb for non-political reasons too, but the vast majority fit the above.

 

That is unfortunate, yeah. I got a lot of good help from several of those guys. Wish I could help more - I feel like I take more than I contribute here.

These days it seems hard to separate life from politics, since it touches so many aspects of our lives. I wrote, then deleted, a post yesterday (in an "off-topic" part of the forum", at least) about somebody not being able to find a "skilled IT professional" for a $21 / hr job... I mean, it would be nice if we feel this is a community of friends in which we could discuss other things (in the proper space), but even in groups of friends, friends get kicked out for being jerks, and we need this forum to be about Tundras more than off-topic stuff.

Edit: look, we're talking tangentially about politics in a thread about ignition coils!

 

I think the regulars here know you're not like the majority of other fly-by-nighters who pop in here. If you look at first page of 1st Gen forum topics right now, out of those 30-40 threads on the 1st page, at least 10-15 of those where it's the person's first post, and rather than make an introduction, they went straight to "this thing failed, how do I fix?", at least 75% of 'em will literally never post here again after that thread. They won't even give members here the courtesy to say "problem fixed, thanks!" which could help others in the future. It's the nature of forums, I guess, but ... it still sucks, pretty selfish, but I guess that's how things are now, thanks to the internet.

It's a slippery slope. Even if there was a 'no holds barred' area to post in, what is the actual gain? Does anyone really think that will help unify the community, foster any actual camaraderie and growth? Or will it just help sow more division, creating beef between members who otherwise wouldn't have any beef in the first place? I think we all know the answer.

That's the problem. Pandora's box, once you open it, the damage is done. I suspect that's why there is no place like that here, for charged topics like politics and religion. It's almost impossible to find places where you don't hafta talk about and read that crap these days, and we can all just focus on the stuff that used to be way more important, like trucks, hobbies, music, food, etc.

I've grappled with whether or not it should be opened up, whether it would help to have a little less authority to boot. After watching other forums who allow it melt down because of it, and seeing that NOT happening here, it's refreshing. I think it's better the mods just don't go there, don't bow down to demands for it.

Back to topic, about those coils. You mention rough running. Is it rough in park or moving? Rough at idle, at acceleration, or in a specific speed range like 20-30mph, 40-60mph, at a specific RPM range?

Also, when was the last time you cleared codes and/or had your battery unplugged for more than 5-10 minutes?

I only ask because the first questions could help pinpoint other issues. If you left your battery detached, ECU will reset, and truck can run rough until ECU has time to recalibrate. If rough at idle only, it could be an issue with engine or transmission mounts. If rough on acceleration or at highway speeds, maybe you need to lube all your zerks between the front diff and rear diff. You get the gist.

If you were misfiring at all due to the coils, you should be tossing codes, or at least having a pending code registered for the cylinder with issues. If anything, you may be seeing weaker spark due to the shape of the coil tube. If I were you, I'd also be checking the plugs next time I had a coil out.

Oh, and don't forget, RockAuto gives forum members a 5% coupon code discount. They usually keep it updated in their vendor forum, but if not, you can also pull codes from www.RetailMeNot.com and maybe other coupon sites. I typically order from SummitRacing because they're fast, beat a lot of other vendor prices, and I can order online and have it ready for pickup by the time I drive down the interstate to get there.

 

To be clear, I am a full-time paranoid worry wart that wants my truck to purr like a well-tuned brand new luxury sedan and feel like if it doesn't then I should figure out why and fix it. Any time I do a major repair or maintenance job I am happy for maybe a day before I detect a new issue to deal with. My wife thinks I'm imagining things and mocks me ruthlessly. My buddy up in Flagstaff with an '06 Tundra currently running on 7 cylinders tells me to "get a life". In other words, "rough" is relative. It could very well be my imagination.

But to answer the question: my main concern at the moment would be "while slowing down and braking" (point #1 below). I also feel a roughness while driving in general (point #2 below). If I put it in Park or Neutral and rev the engine, everything feels smooth, and I don't generally feel a difference at different speed or RPM ranges (other than slowing down at a stoplight).

I feel two possibly different things.

1. When braking / slowing down, I sometimes feel ...stumbling, pulsing, something like that. (It's not ABS engaging, I know what that feels like.) I originally thought of brakes, and this thread was enlightening. I feel like refreshing the rear brakes did clear up some pulsing, but I feel like there is still a stumbling going on. I do not feel like it is warped front rotors, or rotor hot spots, but more "in the system" somewhere.
   
   I would still be going down a brake-system rabbit hole – master cylinder? water in the brake fluid? etc. – but when I mentioned the pulsing to my wife she told me she had a very similar problem with her old Ford Escape that was caused by bad ignition coils. She ended up replacing those and the problem went away. In searching symptoms of bad ignition coils I did indeed find my exact symptoms, so here we are.
2. I feel like there is a ....grinding? at all times. I feel like there is sand in the wheel, like it just feels and sounds rougher than it should. I've had the bearings (and everything else) checked several times, and every time I just get told "your tires have cupping (true) and that's what feels rough. Until you get new tires, you'll have to live with it." I am now wondering if it is actually the engine (ignition coils) causing this sensation.

It has been a long time for either of those things, and the issues I'm describing have been going on for a long time, too.

I did, and have a couple of times in the past. This most recent time I replaced all 8 plugs with new Denso

$4 K20R-U Denso 3122 Spark Plug

K20R-U from RockAuto gapped to .031, since it had been 30K miles since I replaced them last. The old plugs looked ok - no warning bells with regards to mixture, etc, and, since I had re-gapped them fairly recently, they weren't too far out of spec.

Crap, I had forgotten, or didn't know. Thanks for that. If I do go ahead and replace the other 6 coils that will save me enough for a case of PBR.

 

I have the same seam cracks on mine at 198k... No rough running, but noticed them when replacing the spark plugs as scheduled maintenance.

I did a little googling afterwards and found people claimed success with wrapping in electrical tape... I'm skeptical. I was thinking of trying wire/cable heat shrink to wrap the coils. I couldn't find any evidence of anyone else doing the same... I may just go ahead and be a guinea pig on it at some point.

 

Stuck valve situation? Or something worse? @kirbotc had same, no compression on 1 cylinder, swapped the engine only to find it was a stuck valve IIRC, and he could've probably fixed that more easily than dealing with all the wild side effects of swapping the engine. (link to thread, maybe this info and the thread are interesting to your buddy)

Both symptoms #1 and #2 are things I dealt with before I thoroughly lubed my drive line. Only I'd add a 3rd symptom, which was a *THUNK* sensation accelerating from a stop light randomly, it felt almost as if I was being tapped from behind as I was pressing the gas pedal down to go forward, best way to describe it.

Is it possible your issue is actually the rotation and bearings associated with your driveline, and not the wheels and axles?

If so ... 5 minutes under the truck may solve a lot more than you'd imagine.

Valvoline NLGI 2 synthetic w/Moly additive (Valvoline part#:

$11 VV985 Valvoline Moly-Fortified Gray Full Synthetic Grease 14.1 OZ Cartridge

VV985) is good for everything on the drivetrain and under $10/tube. When get to doing the slip yoke (see #B here), if yours has never been done before on your watch, in the last 10k-20k miles or more, it may seem like it's not taking any grease. Before lubing it up, read this for instructions on how to handle that specific zerk, it's an oddball, threw me for a loop! For some of the zerks, swapping to a side-load fitting like this may help:

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So that 3rd symptom sounds like a bad center carrier bearing. I had that symptom too. I replaced the carrier bearing and the "thunk" (and $500) went away.

Possible, but mechanic says everything is ok. He (presumably) lubed everything as recently as when he did the timing belt / water pump job about 1000 miles ago (and the symptoms I'm describing go back way longer than that).

Ha! Thanks for the link. I'd read about people getting an extra fitting and grinding it down to get to that zerk, but if that product works I'll get it. Either I or my mechanic lube stuff regularly, but being able to get that one myself, too, will help my peace of mind.

 

I would try a little jb weld in the crack applied with the finger tip and smoothed out. I have eliminated misfires on coil packs by replacing the boot and spring for $5. I replace all the boots and springs when all the spark plugs are changed.

 

Shockingly, all symptoms went away after lubing my drive line, including the *THUNK*. Hasn't happened once, and I think I lubed everything up before the pandemic started? I'm probably overdue again.

Link to it and my preferred grease was automagically added at the bottom of this thread.

I really think what did it was spending the extra time, grease, and attention on the slip yoke. As stupid as I felt doing it - since I've never bothered to do it on any other vehicle, jacking that zerk full of grease, then jumping up and down on the bumper, before jacking in more grease, then jumping up and down on the bumper, then popping off the zerk to release the excess grease out - at least I walked away with the confidence that (1) grease was definitely getting in there and (2) moving all around, all over everything, and (3) the visual proof of both was apparent when I popped off the zerk, and (4) any excess in there came out after was priceless.

That's the only thing that really bugs me about vehicles I own. I've owned dozens of cars in my lifetime. Until I finally touch on everything and get it to a "known value", I'm always questioning everything. I still haven't finished getting to that point with all of my fluids yet and it's been eating at me for a hot minute now. Tranny, power steering, brakes, coolant.

 

Ah, cool, I'll try that, thanks for the idea. I've got some JB Weld for emergency field repairs, but I've never actually used it. This will give me a chance to give it a try and see if the cracks affect the ignition coils.

Yes, exactly! And, once I finally get everything to a "known value" either the first things I touched need attention again, or the whole vehicle needs to be replaced, so it's a never-ending cycle.

(The latter is one of the reasons I'm being extra attentive to my Tundra: I want to keep it forever. It has 150K miles now, want to get at least 500K, right? At my current rate, that's about another 20 years...)

 

JB weld is strong, but it also contains metal particles for strength. Asking because I don't know... wouldn't it be better to use a non-metallic high temperature epoxy if filling the cracks?

 

Sure about that?

https://gluenerd.com/does-jb-weld-conduct-electricity/

JB weld doesn’t conduct electricity. It’s an electrical insulator with 50% calcium carbonate and 30-40% epoxy resin. JB weld is heatproof and pressure-resistant in liquid and hardened forms. It’s used for medical electronics, communication devices, and microelectronics to extend device longevity.
​

Or take it straight from the horse's mouth:

​

 

Obviously not... I thought I had read/seen that they used metal filings for strength. I was mistaken.

 

I actually remember someone telling me this in the past also, and me telling others the same, so know it's not just you. My reply probably came off jabby, it wasn't intended to be.

I only found this out recently when I needed to glue down the antenna on a wireless router I had a few years back, direct to a PCB. There are other similar bondo/epoxy type products out there with metal in them, though.

 

I haven't had to try it on a Tundra, but I have had luck restoring old coils by sealing them with high temp silicon.

 

Those tiny cracks (and even large cracks) in the outer sheath mean absolutely nothing. There are multiple layers of insulators and windings to get through before the ignition spark could even reach that crack and then jump the air gap to the spark plug tube. Don't waste your money on new coils or even bother with JB Weld or anything else to seal the cracks if your engine is running fine and you aren't getting any codes. See pictures and notice that the one I cut through has a cracked sheath as well, but it was just fine.

 

Question: my truck is almost at 300k miles.
From PO service history, I can see that they replaced 1 spark plug here, 1 ignition coil there.

I'm definitely going to be replacing all the spark plugs to get to a known position because they're cheap.

Is it worth taking the same mentality to coils? Do coils slowly wear out like sparks and I would see benefit by replacing them?
When I browse forums I see people only replace them when they crack, just like this thread.
That gives me the impression that they don't wear out, they just fail eventually.
What's the truth on this?

 

Let's not continue this topic much further, I just wanted to shine on a common truth
Truth that humans are human and have been since humanity began in the world.
And found it to be a chaotic and fleeting world, when all we want is order and security.

We are in constant pursuit of security for tomorrow, so that we may enjoy today, to reminisce on yesterday. Never realizing that tomorrow is never today, and yesterday was just today worrying for tomorrow which never came.

We are no more inseparate from politics today than any yesterday or tomorrow as we are no more inseperate from insecurity.
The first - and most obvious - way of overcoming an insecurity is to loudly proclaim how much we aren't affected by it. How much we control the thing we fear we can't control.
This has little effect as most of us know, other than to communicate that it really is something that bothers you.

There is a time and place to be insecure.
There are ways and thoughts of mind to handle insecurity and security.
Socially, we agree to put these aside in the interest of socialness, because these issues are deeply personal and founded in our own individual realities.

As `Shifty mentions

The answer, as he hints, is that our insecurities are tied down into the foundations of our ego - our sense of self as an identity.
There is no community in the ego.
It is ego-centric.
There is no concern, nor gain for the community because the loudness of insecure politics is a group of individuals exclaiming - quite loudly - how they share the same insecurity and it is evil of us not to see it the same way as them.

And there is nothing for anyone else to do for them because their issue is their issue in their reality of their reality - in exactly the same way that the issue of them being loud is our issue of our reality and not theirs of theirs.

And no matter how much you wish to help, alleviate, or mediate: the fact is our realities are separate. Our experiences are experienced individually, and so to do we experience our security and insecurity.

That is the beauty of community - sharing our experiences individually to create a larger whole that no one truly is, out of individual sums that we all are, so that we all may benefit when in need.
Keep the essence of community in mind when in the horror of the hive minded Borg, from Star Trek.

Security is futile
We can only control ourselves
Not the world that presents itself to ourselves

The nature of nature is impermanence
We will never stop being scared: because through ego, it is scary.

Anxiety feels like falling
Happiness is trusting where you'll land

Your flagstaff buddy sounds pretty wise.

Which is to say, get a life full of problems you enjoy. Not problems that seek security in tomorrow, but problems that let you enjoy your truck today.

 

At 300k, I legitimately think you've gotten your fair value/use out of the factory coils, we've seen some members lose coils on their trucks in the 150k-250k range. Anything over 250k miles, you'll likely notice a significant difference replacing coils and injectors.

Only buy Denso brand from a legit source. The OEM coil packs fire hotter than aftermarket.

 

Yes, everything eventually breaks down. But unlike spark plugs that lose bits of metal and ceramic over time I believe, outside of terminal connection failures or any electronics components, the insulation on the coil windings just degrades and can fall apart over time causing coils to short and fail to produce the voltage uplift they were designed to provide. I believe this occurs by heat cycles and vibrations over time rather than directly by the current that passes through them. At 300K miles and I'm sure a couple of decades of use, those failures might start to show up. However if you do a resistance test on the coils designating pin 1 as the pin closest to where the bolt holds the coil to the head. Resistance from Pin 1 to Pin 2 should be in the neighborhood of 350 ohms and pin 1 to pin 4 should be around 22,000 ohms. If the coils are near these values the spark produced by them should not be compromised and thus you would not likely see any improvement in performance by replacing the coils but you would gain confidence in their reliability for another couple of decades. I would hang on to some if not all of the old coils if you do change them to use for troubleshooting or quick replacement stock in the future since you know they were performing fine when you pulled them out.
As Shifty has stated the fuel injectors could be well worn to the point they are not producing the fine spray that they should and instead are spitting droplets into the cylinders. I have seen SIGNIFICANT performance increases by replacing worn injectors but I've never seen any increase in performance or economy by replacing a coil that hasn't failed and tests good.