That's a New Problem

I spent last weekend at the track and kept having to pull into the pits with misfires. Same issue every time-plug wires popping off.

I'm sure I can fix this with a cover, but I'm pretty confused as to why it happens in the first place.

Same cylinder?

Get new plugs, they are leaking.

Im not doubting you, but can you explain? I cant picture how that would happen without a plug being physically loose. And audible. And a constant issue regardless of track/street.

Wrong wires? Can you squeeze the (metal) part that clips on the top of the plug with pliers gently through the rubber?

I second the question "same plug wire every time?"

Dusterbd13 wrote: Im not doubting you, but can you explain? I cant picture how that would happen without a plug being physically loose. And audible. And a constant issue regardless of track/street.

Maybe the ceramic is not sealed to the electrode any more, leaving a compression escape path right up through the center of the plug.

Would also be the perfect location to blow off the plug boot.

You can actually see what happens in the picture above. Plug 3 popped off half a dozen times, only on track.

The plug is leaking. Either past the seat washer, past the internal gas seal washer between the shell and the insulator or past the internal gas seal and right up through the center of the insulator.

Crazy that 2 plugs would leak simultaneously. Can't be a common plug failure mode and 2 both did it. 3 seems downright unheard of, unless maybe you got a bad manufacturing flaw batch.

Those plug wires look to seal to the valve cover too - have excessive crankcase pressure?

(Plugs are an easy and cheap thing to try though).

Edit: reading comprehension fail. Plug 3 not 3 plugs.

Is there any oil around the plugs in those tubes?

I saw a bizarre plug wire disconnect on a Toyota 5S-FE once. Oil cap was left off, so some oil got splashed onto the valve cover. A little big dripped down into one plug tube and went un-noticed. Put the cap back on, wiped it up. All seemed good.

When the car was taken on the highway, it was fine for about 15 minutes, then the oil got warm enough to start vaporizing some of its more volatile compounds within that plug tube. A little stray spark and I was greeted with a very loud pop and a thud, followed by a dead miss on one cylinder. The oil vapors exploded and blew the plug wire off. The thud was the wire hitting the hood... The bottom of the wire boot (where it meets the plug) had scorch marks on it when I checked it out

Wiped out the plug tubes, put in new wires and all was well.

Old wires or incorrect installation.

Does the wire snap onto the plug ?

Strange. I had a similar problem with my brg, but the wires kept popping off the coil. Turned out to be bad wires, the clip in the boot that connected to the coil stud was wrong.

I'd venture to guess that the extra cylinder pressure from the snail while at peak power levels may be wrecking havoc on your plug's structural integrity.

This is on the turbo tuscani?

Try swapping plugs first. There was a run of these cylinder heads that had very small cracks around the spark plug tubes. Apparently they would crack when the tubes were pressed in at the factory. I hope that's not it but FYI.

Got any oil in the spark plug tubes? If it's not the spark plugs being loose or having a bad seal as others have said, it could be the gasket that seals the valve cover.

I had this happen to my Accord for a while. It ended up being leaking gaskets around the spark plug tubes combined with excess crankcase pressure/blow-by. (it was a 350,000 mile work beater).

So I just pulled the part that sealed to boot to the valve cover back a bit, so that pressure could not build up in that tube. Worked fine till I sold it 10,000 miles later.

appliance_racer wrote: This is on the turbo tuscani? Try swapping plugs first. There was a run of these cylinder heads that had very small cracks around the spark plug tubes. Apparently they would crack when the tubes were pressed in at the factory. I hope that's not it but FYI.

So Hyundai did it before Honda (3.2/3.5 V6 ~2012-2014)