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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #1
Dropped off the CTS at my dealership to have them replace the front driver side lower control arm. Yes I know it's a fairly easy repair but I am finding that I no longer have the time to spend 3+ hours pounding on suspension components with a ratchet and a rubber mallet because I dont have adequate air tools.

Anyways the day I dropped it off it was about 18 degrees outside and the engine only had maybe 2 minutes to warm up before I had to drive it. As I was backing out of my driveway I noticed the CEL (not flashing) and mentioned to the service adviser to please check it out and let me know.

Anyways he called today and didn't mention specific codes but did say in order to fix it, they would perform the following services.

1. "de-carbonize" my engine. To me that just sounds like my intake is dirty and needs a good cleaning.
2. fuel injector flush. Again, this just sounds like maybe they are dirty and need to be cleaned.
3. throttle body service. Again, this just sounds like my throttle body is dirty and needs to be cleaned.

My question is, what would you do to fix these issues yourself. No way am I paying someone 600$ for something I can easily do myself. If the check engine light is still present when I get my car back or pops up again as I am driving, I will pull the codes and update the thread.

Note: the past few mornings when it's been cold outside, the engine has had what feels like a misfire. It's stutters for a few seconds here and there. Once it's warmed up the problem is no longer present even sitting at a light. Stomping on the gas doesn't produce flashing CEL.

My timing chains have been replaced and I've only driven maybe 4 to 5k on them.

Thanks.
 

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'05 CTS-V
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Sounds like 3 loads of crap to me, particularly since they didn't even tell you what the problem is that they're going to "fix". :rolleyes: Unless your car has a couple hundred thousand miles on it and you have a habit of running cheap, garbage gasoline, there's little reason to think that anything in the fuel system needs to be cleaned. And I've love to know what exactly they do to "de-carbonize" the engine, or what a "throttle body service" is.

FWIW, contrary to popular opinion, idling your car for minutes at a time to warm it up is actually not very good for it. An engine will get up to its normal operating temperatures (where it operates most efficiently) more quickly when it has a load on it; sitting at idle there is no load.
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #3
Yea those were my thoughts exactly. At first I thought he was talking about doing a top end cleaning but as he kept trying to explain it to me I just got more and more lost as to what he was talking about. I kept asking if there was an issue with a fuel injector but he said there wasn't, they were just dirty.

I understand an engine can get carbon build up but that's to be expected. Since he couldn't tell me the exact code, and they will erase the code(s) before giving it back to me, I just plan to drive it until the CEL reappears and then pull the code myself.

I do regular fuel treatments every couple of months using a bottle of seafoam or techron on a nearly empty tank. I only use Shell 93 octane. I change my oil every 3k with Royal Purp 5w30. I only use WIX or Mobil1 oil filters. For having 130k, my car is in pretty good shape mechanically.

I figured to make sure everything is in working order once I get my car back, I'm just going to pull the intake off, inspect the fuel injectors and spark plugs, replace the fuel injector o-rings, and then replace my fuel filter since it has yet to be replaced.
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #4
Got my car back today. Misfires on all cylinders. Looks like I'll be pulling my plugs this weekend and swapping around some of the injection coils.
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #5
Just got the upper intake off. While the upper intake is dirty and the black hoses going into the intake had oil on them, the valves themselves were pretty much spotless. Since I had a misfire on 5 out of 6 cylinders (1-5), I'm just going to replace the spark plugs with autolite double platinums. Should I even bother to switch around the ignition coils? I find it more likely to be the spark plugs versus the ignition coils. Then again someone on here with more experience might have another suggestion.

Also, the black brittle hoses that snap into the upper intake. Where can I find replacement o-rings. They're little orange o-rings and the ones currently on there are slightly torn in some places.
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #6
Well I found out what was wrong. 5 of the 6 ignition coils were broken and seized to the spark plugs. I've spent the last 2 hours digging the boots off the ignition coils, out of my damn spark plug wells. Not to mention, the 5 ignition coils that were bad, also had stripped bolts. I guess billy badass at the dealership though they had to impact wrench everything back when they did my timing chain job since you have to remove the ignition coils and valve covers in order to take the front cover off. At this point i'm thinking of just breaking off the tops of the spark plugs so I can pull the rest of the boots out. Also, one of my ignition coils had a **** ton of calcium buildup.
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #7
Finally got it all fixed. Cleaned out the spark plug well that was rusted. Didn't have to break any spark plugs to get the seized ignition coil boots out but there are plenty of videos on youtube that recommend that method versus digging it out. Replaced all spark plugs with Autolite Double Platinum plugs. The NGK Iridium plugs I had in there before weren't insanely dirty but did have oil/carbon build up on them here and there. Replaced 4 of the 6 ignition coils with AC Delco ignition coils. Within a few seconds after starting it up, the check engine light I had went away.
 

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06 CTS Sport/Luxury package
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Glad to hear it my friend.

Now even the check engine light went away. Have it read, take a picture of the OBD2 scanner's screen for the codes and have them cleared. I just like to keep records of stuff, there's no real need to have the codes at this point. Other than something to fall back on just in case 100,000 miles later it happens again.

KOT
 

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2006 3.6L CTS, Hotchkis Sway Bars, FE2
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526 Posts
Discussion Starter #10
I know you weren't getting many replies, but I was following along, and I'm sure others were as well. Glad to hear you get it cleaned up and CEL-free.
I thought about not finishing the thread and just abandoning it but then I remembered how much it annoys me when other people do that. Anyways obviously water and air cause oxidation my only concern is why only the spark plug well closest to the firewall on the drivers side of the engine? It was the only spark plug well/spark plug that was rusty. It was however one of the 4 spark plug wells where the bolt for the ignition coil was seized in the valve cover insert. For example if you walked up to my car right now with the upper intake removed, you could pull out the ignition coil with no problem.

To combat this, I put some die-electric grease around the top of the ignition coil where it mates with the valve cover and the rubber part of the ignition coil that fits inside the top of the spark plug well.

Hopefully that will solve the problem.
 

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04 CTS Base, 3.6, 07 CTS Base
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Sounds like 3 loads of crap to me, particularly since they didn't even tell you what the problem is that they're going to "fix". :rolleyes: Unless your car has a couple hundred thousand miles on it and you have a habit of running cheap, garbage gasoline, there's little reason to think that anything in the fuel system needs to be cleaned. And I've love to know what exactly they do to "de-carbonize" the engine, or what a "throttle body service" is.

FWIW, contrary to popular opinion, idling your car for minutes at a time to warm it up is actually not very good for it. An engine will get up to its normal operating temperatures (where it operates most efficiently) more quickly when it has a load on it; sitting at idle there is no load.
But when it is very cold out, ours will idle for 10 mins, in the morning. Have done this for years, don't know that it has hurt anything. Might waste a little gas, but that's alright if its warm and cozy for the DW when she goes to work. I might even go out and start it for her, sometimes.
 
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