Spark Plug Failure

[shatto]

Here's a novel way to start the new year.

Clyde the Ride began the year with an occasional feeling, as if the axle had come loose. How do you think I know what that feels like?
Anyway, it was a surge - sort of like being pushed in the back. Today, as I was on my way to pick up stuff to deliver it, the slight surge increased into a constant shuddering under any power at all and the 'check engine' light lit, so I called my dispacher and cancelled my availability and drove directly to Dex's garage.

While Dex was trying to get the scanner to talk with the computer, I noticed a light tan colored powdery stuff on the shiny, clean aluminum of the oil filler tube and valve cover. Then I noticed a slight 'poofing' of the rubber seal of the coil each power stroke, as the engine idled roughly.

Hmmm? exclaimed the both of us.

We removed the coil and the sparkplug.
The long probe of the coil that inserts deeply into the tight cylindrical chamber (Damn! this is a sexy engine!) to contact the plug had the rubber tip severely cracked. Then Dex showed me the plug, by slipping the ceramic part back-and-forth inside (there I go again!) the steel base.
The seal had completely blown out of the plug!

We installed another plug, and I went on a test drive. Aaaaaaaaak! Still missed.

Went home and put all eight of the stock plugs back in. Another test drive. Another; Aaaaaaak!

The Toyota Dealer is nearby so I dropped by to see what I could find out; what a Coil-pack cost ($105.00) and if they could bench test it.
The Service Writer is a pretty good guy, willing to actually talk with me. He asked the tec-guy in the back and returned to tell me that they don't bench-test, they simply move the coil in question and if the missing happens in a different cylinder they know the coil is at fault and they then have to find out if it failed completely or if it is arcing or shorting somehow.
I lept from the chair shouting; "Eureka!" Well I didn't really, but that sounds better, anyway I figured out, in the most brilliant fashion that, if you have a big old crack in a rubber boot, inside a steel tube the probability is the spark would jump right to it.

So, I sped, no, limped home, parked Clyde, removed the coil, cleaned it up with Brake Cleaner (no residue) and whipped out my magic fixer.........................no, not JB Weld.........this is: X-Treme Tape, by Vypar.

X-Treme Tape is the stuff that sticks to itself then vulcanizes so it never comes undone. Stretched it as it was applied a couple wraps around the torn tip then waited a few minutes for it to set. And heat makes it set faster. And it was going into an engine......

Insulates to 8,000 Volts. Won't melt, up to +500 degrees. Air and water tight. Flexible to -60 degrees.

Know why I like this stuff?
Clyde runs right again.
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[VetteOwner]

it might work for a little bit but will eventually wear again...

i believe most coil packs dump out around 40,000 volts. (your gas BBQ grille ignitors are about 14,000 volts :P)

coolant temp is under 200 but manifold can be easily twice if not 3X as much(especially around the sparkplug/exhaust area)

it is good that its water tight as even a foggy day can cause misfires or condensation on the block (used to happen to my s-10 in the mornings, start fine idle fine any type of load it would stumble and fall on its face)

dang $105? seems like a rip i dunno what to suggest for that... i tried a autozone search for a coil pack for it and doesnt even list one. might get lucky in a junkyard.

[shatto]

The assembly of a sparking plug is, I think; the ceremac part of the plug is inserted into the engine side of the steel seat, then the electrode is welded on. There is a seal to prevent gas leakage, but in this case, it failed and blow-by and the wobbling of the ceramic part broke the rubber of the coil extension. It was, in fact a Pulstar.
Like this:
(the seal is the red part directly below the word Pulstar in the picture)


The sexy looking coil-pack:


The tip, in the bottom left of the picture is the rubber that seals over the end of the plug. It split lengthwise.

[VetteOwner]

ohh those kind of pesky coilpacks... it might be ok but if it starts doing it again id imediately look into that one u taped.

ive had the normal sparkplugs ceramic just crack and cause similar symptoms. THOSE are hard to diagnos especially when its just a hairline crack

[kamesama980]

$105 isn't bad for a coil-on-plug coil I would expect $150+ from parts stores, twice that from the dealer.