NEED HELP Wet Coil Pack on CL#06

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Hello everyone,

I have a 04 Trailblazer LT with 93k miles on it and i had a misfire on Cylinder #6 the other day and i decided to check on the coil pack and i found something quite strange my coil pack had a small amount of water on them and around the sparkplug! where did the water come from? I didn't wash it or the engine compartment and coil pack seal seemed to be tight, it was clear water no smell or color to it
also no oil, i took a thin white towel and dried it out and it came out pretty much clear, I'm using red antifreeze coolant so i guess can eliminate head gasket issues?

I'm quite perplexed i have never encountered something like this before, any ideas?

P.S. i have checked the rest of the coil packs all of them are dry and clean.

Much appreciation for all of the people on this awesome forum.
 

xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y

Although this thread is for the # 4 I'm pretty sure its the same issue. It might be a matter of how your truck is parked, a slight upward angle at the nose and water will make its way back there.
 

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE

Although this thread is for the # 4 I'm pretty sure its the same issue. It might be a matter of how your truck is parked, a slight upward angle at the nose and water will make its way back there.
Thanks man, I'll check hood seal it could be it since the #6 coil is almost directly under rear the edge of hood, i thought that the coil pack seal should prevent such thing from happening... Another flawed design by GM i guess 🤷‍♂️
 

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Sorry for bumping my post,

Another issue I'm trying to figure out, the car started to misfire a couple of days ago but no codes were showing i thought I'd take the negative terminal off and let it reset for a couple of hours after resetting it I took it for a small drive it started to misfire again with the check engine blinking and give me "P0306 misfire cylinder 6" that's when i found out about the water on the coil and the sparkplug I've cleaned it and switch coil #6 with coil #4 to eliminate it as source of the problem took it for a 20 min drive it still misfiring but no codes are showing,

I'm wondering how long does it take for engine to throw a misfire code? When i did it first time it showed an engine code almost in instantly.

Also can both coil pack and sparkplug be bad due the water condensation? I've replaced the sparkplug recently.

I'd appreciate any help possible.
 

xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y
Your best bet is to get an elm327 and torque app to see live data on which coil and or cylinder is missing. Otherwise just wait for your current code reader to give you a definite hard code as to which cylinder it is. We all get a P0300 at the start of any misfiring and then a few drives later it will give exactly what cylinder.
You did the right thing by switching the coil pack now its a matter of is the coil shot or did the water jack up the spark plug.

Q: What plugs did you use when replacing?
 
Last edited:

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
Your best bet is to get an elm327 and torque app to see live data on which coil and or cylinder is missing.
I have a cheap ODBII scanner and torque app installed, i did try to monitor the cylinders however readings all over the place no consistent readings on any of the cylinders sometimes it shows 0 reading on CL#01 then 192 on the same cylinder i thin the ODBII is not accurate... I'm planning on getting something better but at the moment it seems unreliable.

You did the right thing by switching the coil pack now its a matter of is the coil shot or did the water jack up the spark plug.
I've used the same method when I replace other bad coil packs and it seemed to work and less expensive. XD
We all get a P0300 at the start of any miss firing and then a few drives later it will give exactly what cylinder.
is it possible to have a misfire and no code showing?

What plugs did you use when replacing?
I've used ACDelco 41-103 plugs
 

xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y
is it possible to have a misfire and no code showing?
Those are the right plugs. You didn't try to gap them by any chance?
 
  • Like
Reactions: Redbeard

budwich

Member
Jun 16, 2013
2,027
kanata
quote... " I have a cheap ODBII scanner and torque app installed, i did try to monitor the cylinders however readings all over the place no consistent readings on any of the cylinders sometimes it shows 0 reading on CL#01 then 192 on the same cylinder i thin the ODBII is not accurate... I'm planning on getting something better but at the moment it seems unreliable."

I think it might be telling you more than you think. It is potentially indicating you have a "multi-cylinder misfiring problem". The reason that you only see a code for the one cylinder is that its misfire rate crossed a bogey and set the code. The other cylinders may not be as bad but are misfiring.
Having said that, it depends on how you are using the scanner... what are you actually doing?
A flashing cel is a sign that you have some "low rate misfiring" happening.

The rate is calculated over different cycles (numbers of revolutions) among other things... hence it could be jumping around. Again, it depends on what you were looking at.

I think IF you are seeing them across cylinders, you have more than a "single wet coil issue".
 
Last edited:

Chickenhawk

Member
Dec 6, 2011
779
There are many instances of misfires suddenly appearing after a plug change. What happens is that the coil pack is not inserted properly on the spark plug. (Easy to do, and it is hard to tell when it is properly inserted.) The coil pack then fails in short order.

I would re-insert each coil pack on all your plugs. If you still get a misfire, then it may be time to replace the worst coil pack and check the code again. It is not that unusual to have to replace a couple of coil packs after a plug change on our platform. And, while a fair amount of water in the hole can cause a misfire, I have seen them run perfectly fine with a small amount of either water or oil in the hole. If it's water, seal under the hood seal with some weatherstripping tape. Works good.
 
  • Like
Reactions: ghost_leader07

ghost_leader07

Original poster
Member
Dec 18, 2019
152
UAE
quote... " I have a cheap ODBII scanner and torque app installed, i did try to monitor the cylinders however readings all over the place no consistent readings on any of the cylinders sometimes it shows 0 reading on CL#01 then 192 on the same cylinder i thin the ODBII is not accurate... I'm planning on getting something better but at the moment it seems unreliable."

I think it might be telling you more than you think. It is potentially indicating you have a "multi-cylinder misfiring problem". The reason that you only see a code for the one cylinder is that its misfire rate crossed a bogey and set the code. The other cylinders may not be as bad but are misfiring.
Having said that, it depends on how you are using the scanner... what are you actually doing?
A flashing cel is a sign that you have some "low rate misfiring" happening.

The rate is calculated over different cycles (numbers of revolutions) among other things... hence it could be jumping around. Again, it depends on what you were looking at.

I think IF you are seeing them across cylinders, you have more than a "single wet coil issue".
Thankfully i managed to fix the issue without the need to replace anything, it appears to be the water is what caused the whole mess after a thorough cleaning and leaving it to dry it seems to be good now, thanks for the help!
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
  • Like
Reactions: xavierny25
Dec 5, 2011
574
Central Pennsylvania
Before reinstalling your coils.... WASH the coil gaskets. I wash mine in the sink with dish detergent to get them completely degreased. If they are brittle and cracking they will need replaced as soon as practical. I do reinstall the cracked ones, though, until I can get replacement gaskets. I also apply a thin layer of vaseline above and below the gasket before seating it on the coil and seating the coil in the valve cover. Also clean the gasket mating surfaces before reassembly (paper towel and electronics cleaner works well). Does it actually do anything? Dunno... but I haven't had water in my cylinders since I started doing this.

Any weather stripping you install goes on the cowl. UNDER the existing seal, if I remember correctly.
 
Jan 19, 2021
18
us
What would that have to do with the ignition coil?
when i first bought my 03 ltz it blew like 3 different packs at different times i was like wtf did some research and apparently some trailblazers with the sunroof something about the drainage channel runs down up under something i can’t remember really but at any rate, moisture from this channel deposits on the coil packs i guess...

i happen to have a sunroof and their suggestion was to purchase new packs with better sealing which i did and they haven’t blown since then a couple years back now
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Well the sunroof drains run nowhere near those coils and drain out in the door jambs. It's the seal on the cowl just above the coils that leaks onto them.

Definitely new coils with better seals on them helps however preventing water from dripping onto them extends their life. Coil #4 is directly under that cowl and often fails like this.
 
  • Like
Reactions: Beacon
Jan 19, 2021
18
us
Well the sunroof drains run nowhere near those coils and drain out in the door jambs. It's the seal on the cowl just above the coils that leaks onto them.

Definitely new coils with better seals on them helps however preventing water from dripping onto them extends their life. Coil #4 is directly under that cowl and often fails like this.
ok well i’m just telling you what i read and my experience with it

seemed to have helped my situation but hey maybe just a coincidence
 

Forum Statistics

Threads
23,273
Posts
637,487
Members
18,472
Latest member
MissCrutcher