09 Acadia Coil Packs Failure

[Nicole Lang]

Hey! So, I'll give you the quick history...  Over the last year we've replaced 3 coil packs. It started with a miss and the dealership recommended a top engine clean and repair of an engine mount. We did that and it didn’t fix it. So they changed one of the coil packs and that did fix it. Then a few months later the miss appeared again and a different dealership replaced another coil pack, at that time at the different dealer they also changed the spark plugs for the other cylinders on that bank (1,3,5 ), the coil pack they changed was #3.
 

Then right before Christmas another coil pack. And now it started missing again and this time I took it to dealer and they said it was the #3 and #4 coil packs.  Which the #3 was just changed in July. That one is covered under the GM 2 year parts and labor warranty and at the local dealer we go to they said they didn't record which coil packs they changed before . But I had record from the other dealership that it was #3 for the one in July. 
 

My question is, what is causing these failures? To have the dealer fix them is like 400 each time! I'm probably going to do the fixing myself from here on if this keeps happening. I just want to understand why it's failing? Are they not gapping the plugs right? I would imagine they are checking for leaks and moisture once they are in there? I’m starting to not have any faith in them and want to understand everything better so I can be more knowledgeable and prepared for our next conversation at least. 

[Jsdirt]

This is the main reason why I tell people NEVER go to a dealer, unless you're still under the bumper-to-bumper warranty. They throw parts, rarely diagnose, and bill HIGH, as you've found out. If you can't change them yourself, use a private garage - NOT any dealer.

 

Usually the #1 killer of coils is a bad, or worn spark plug (or an open secondary). Also, they could be gapped improperly, or, could be a bad run of parts. Increasing the gap too far is the same as running a severely worn plug. The energy required to jump a wider gap increases exponentially. Back in the day, coils were built to handle this pretty well. These days, everything is made by the lowest bidder - in other words, they have zero tolerance for wide gaps or opens on the spark side of things (secondary side).

[tbarn]

Check grounds G112 and G114. They are ignition coil grounds. Both attach the cylinder heads. One in the general area of the water outlet facing the front of the vehicle. The other is on the rear head on a stud holding the power steering hose. Don't just look at them. Remove, clean and reinstall. 15 lb-ft.

[tlaw91]

The 2009 model years have the legendarily bad coil packs!

Sorry to hear about all them going bad however it’s not totally uncommon.

They only ran those for two or three years before switching to a much better design, but you having them all go bad at once isn’t unheard of.

Hope this helps.

-Friendly neighborhood GM tech


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