Coil Pack Arching To Sleeve In Head

I was doing my 60k service the other night and I found that a hand full of my coil packs are arching out the side of it to the inner side of the head. The arch is originating from the joint of the metal down tube and the plastic nipple that the rubber plug boot is connected to. I have reached out to three different techs, from three different dealers, in three different cities now.

The first said that this is not a problem and it is okay. Really just shoved this off and moved on with their day. I was not pleased with this so I went to another dealer and and asked a tech there.

This one said that this was a big deal and I needed to get new coil packs for the ones that are presenting this issue. Granted the tech that I reached out to is a friend of mine, but he connected with the rest of his cohorts and they all agreed on this. With two conflicting answers, I wanted a third.

This time I reached out the the fleet service manager that I bought my rig from. The tech he looped into this has said basically the same think as the first tech. They told me that if it was an issue it would throw a code and it has to be dust coming in through the seal. I tried to remind them that computers some times screw up just like motors. I really felt with this one that they treated me like I was some chump that does not know jack.

Has anyone else had this issue with their coil packs? Did Toyota get it resolved for you? I am not pumped on buying new coil packs... Forgot to mention that this service is past your warranty and their is ZERO way they will pay for it.

I did take a picture of it. Unfortunately I took it after I looked at the pack with a confused look and wiped the carbon residue off with my thumb. What you are seeing is where the heat from the arch is burning of the coating on the metal down tube. The location again is on the low side of the metal tube at the joint with the plastic end that has the rubber coupler for the plug end.

 

New plugs installed?

 

Yes. I installed new plugs.

 

What a stupid thing to say, but typical of some of the newer techs these days; no code, no problem.

The coil pack shouldn't be arcing to the wall. If you don't want to spend the money on new coil packs, you could wrap those locations with a couple of layers of electrical tape, but I'm not sure how it would handle the heat, or put a healthy coating of dielectric grease over the area.

 

Are you assuming they are arcing based on that spot of corrosion? Any misfires or roughness? That picture doesn't show any signs of arcing specifically, no pinholes or spider web/lightning bolt like patterns burned in. I don't see any burning, either. Not saying it isn't arcing, just don't see any of the classic signs. Carbon looking dust/residue could be a result of fretting against a metallic surface.

 

Agreed, I'd think you'd see darker marks
I'm no tech though

 

What did your old plugs gap?
Plug wells are 'dry'?

 

Have anymore pictures? My first thought was just corrosion, maybe from some water in the hole during an engine wash. I've replaced a fair share of caps and rotors, that doesn't look anything like that type wear from arc strikes.

 

I assume arching because of what appeared to be carbon build up from burning on the side of the pack (stupid me wiped away before taking the picture). Also what appears to be burning on the metal coating. It also is on the inside of the plug well on the inside of the head isolated to the same area as this joint.

Plug wells were dry. I did not gap the old plugs. They were the ones from the factory and just tossed em.


The things that are throwing me through a loop are:

- this is not the only coil pack with this issue.
- it is in the same place on all the affected.
- it seriously looks like a burn and not rust from my end.
- I have experienced a couple misfires randomly early in the morning.
- no codes have been thrown.
- the same residue is on the wall of the head as well in the same isolated spot.

I guess it coming from the joint could mean it is a poor seal and it is rust and dirt. I would expect that to also throw a code considering it would have to travel down the coil pack to the joint and escape out there. It is then just gumming up the entire inside of the coil pack killing and solid connections inside. Either one of these options is an issue because it is reducing the power sent to the plug for burning the fuel.

I am at a loss. I do understand it could not be arching and could be a dirt and dust issue. I just can't see how two dealers and multiple techs can say this is not an issue.

 

I asked about plug gap because, afaik, the ecm will increase voltage to the detriment of the coil.

 

Did not know that the ECM on these would do that. Interesting. So you are thinking if the plugs were gapped incorrectly (too large) it would over load the coil pack in a sense? That would seem like a engineering failure to me. If the ecm is able to overload a coil pack because of an over gapped plug so much that it fails seems like an issue. I'll dig out the old plugs later today and check. They are buried in my shop trash...

 

Does the ecm command more voltage? I've never heard of that or that the ecm controls the spark voltage in any way. A larger air gap will require more voltage to bridge, all else equal, but that is just a function of Ohm's law.

 

no misfire codes, or rough idle? that corrosion is just that.. corrosion. and if you want you can put a piece of electrical tape over it, and test your theory. or wait a while and check them again.. slight carbon buildup could also be from a spark plug tube seal leak on the valve cover. worst case, you get a new set of coil packs... Delphis are around $45, or you can get NGK's for around $120 each through rock auto... or you can get a full set of 6 TRQ's through A1Auto

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