What would make a coil keep failing?

I have a Jeep Renegade that has been stone reliable for 29,000 miles. It has been treated like a Wrangler having gone over Engineer, Black Bear and many others. With the lift and tires it has been flawless.

However, in the last 500 miles it has eaten three ignition coils, all on the same cylinder. Coil failure is pretty rare but the dealership (its under warranty) says they just failed, all three of them. That seems far fetched to me.

Any suggestions on what could be the cause or what I can check? Any help is appreciated.

 

Too high a voltage (ie current for a fixed resistance)? Why just one cylinder is the question....

 

Swap a coil from another cylinder and see if the problem follows the cylinder.

Have plugs been replaced?

 

No sir they just keep replacing the coil (coil on plug). Looking at the paperwork, they did not check plug gap either.

I will have to wait for another failure to do the swap you mention. Hopefully there wont be another failure.

 

If you unblock your profile page, I'll PM you what's going on. High security on the beeb these days.

 

Coil failure isn't rare at all. Ask anyone with a 5.4 2 valve ford. After the second one I'd be looking into it more. 29k isn't much for a modern spark plug, but it would have been changed on the second coil failure for sure. High resistance can kill them quickly. I'd be watching firing voltage on an O-scope to see for anything odd.

 

I'd put a set of plugs in it and not have to deal with another coil failure.

 

I am not sure how it got locked so I have no idea how to unlock it.

Let me see if I can figure it out.

 

Why not post what is known so the next guy knows?

 

I know it's a douchey move, sorry man. I would have preferred to just PM and not post in the thread at all, for professional reasons.

 

I'd like to see that PM I'm more curious now.

 

Really sorry dude. I think I fixed it. If not, no worries. I do appreciate you and all who have posted here for helping. Its been pretty frustrating. I love that little Fiat, I mean "Jeep"

Its surprisingly capable for what it is and I would hate to get rid of it.

 

Lol. That’s the community spirit!

 

Only a chrysler owner would be proud of being reliable for 29,000 miles. Glad you think you figured it out at least, 3 coils in 500 miles let alone in 29,000 miles is unacceptable.

 

Oh I agree but lets be clear, that thing is not a Chrysler. Nor a Jeep

Its a Fiat Panda.

You have a good and accurate point though.

 

Odds are really good That cylinders voltage is going too high and is killing the coil. Most likely a plug issue but also could be a saturation issue with that cylinders coil caused by a driver crapping out. They should really be looking at the primary ignition side with a lab scope under varying conditions to isolate the issue at this point....
They’d be buying it back if it was mine and it did it again.

 

If it's still under warranty, at what point do you start thinking lemon law?

 

Different by states and certain criteria have to be met. May not even qualify due to mileage.

https://lemonlawusa.com/