Decarbon DI Engine

Does anyone have experience performing a decarbon procedure on the intake valves of a GM DI engine? We have an Acadia 2010 with codes P0300 and P0301. It looks like cleaners introduced through the fuel will not clean the intake valves in these engines. I can certainly figure out how to dribble a liquid into an intake but it seems fairly risky for someone with no experience.

2011 Cadillac CTS | CTS VIN D Service Manual | Document ID: 2863222

None with GM engines

Just with those Fockers that started that trend in mass production - VW & Audi, and BMW.

I am sure you’ll get a host of “how to’s” from snake oil to media blasting with crushed nut shells…but in the end I’ve found that removing the intake manifold and cleaning the intake ports by hand (yes by gloved hands) with cans of carb cleaner/brake cleaner (the kind that is NOT sold in California ) old toothbrushes /other small non marring bristle brushes, and time - and patience.

The last engine I did this on was a V10 Audi - took some time, but the results were great.

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Permanent solution to GDI intake valve carbon buildup:

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Methanol injection? :smiley:

If this is NOT a direct fit for the GM engine in the original post - then I don’t see how this is supposed to be beneficial to his direct injection port cleaning issue.

If the ecoboost kit does in fact fit the above GM application - then please disregard this post

It’s called a joke. I know your cars are from Germany, I didn’t realize your sense of humor was too.

That said, if he’s got the 4-cylinder, I think this is a direct fit:
http://www.performanceautowerks.com/catalog/product_info.php/werksracing-turbo-direct-injection-additional-injector-kit-p-2054

Nothing on the market yet for GM’s direct-injection V6. If you bought a GM V6, that’s a mistake you’ll need to live with. The overarching point here is, OEMs are starting to realize GDI introduces significant maintenance issues on its own, and are starting to implement supplemental port injection as a solution to those issues. Toyota and Ford both come directly to mind as automakers who have determined this is the best way around the problem.

In GM’s defense, I managed 140K miles with no engine issues. I think that’s close to end of service life for a GM right? Now I have rough idle P0300/0301, bank 1 catalytic converter issue P0420, and very noisy cam adjusters at startup; the last two popped up in the last 1K miles.

I’m contemplating replacing the plugs and physically decarboning the intake since both require removing the intake manifold. I’d like to get the engine running a bit cleaner before replacing the catalytic converter. At least this should fix the MIL indication which will fail my next inspection.

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You don’t have to defend GM from anyone.
I’m not a fan of GM but the simple fact is that GM & ‘modern’ vehicles are lasting longer no matter the manufacturer.
Here are a couple of photos from before and after intake port cleaning by hand.

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Modern cars are doing so well I even bought a Ford!

Just wish mine was one of the fancy ones that had supplemental port injection. If I have this thing long enough to need a valve cleaning, it’s getting that kit from up above.

Still though, GDI isn’t a new thing, I’m frustrated the whole industry took this long to do something about carbon buildup.

Wow. I wish I could get that close to the valves on the GM 3.6L LLT. Looking at videos the valves are about 3" below the intake mounting surface.

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Hey, at least I’m glad walnut blasting didn’t get rolled into the “snake oil” category this time!

I’m still bringing my car to the 'Space to do that, you just watch; got everything except for the walnut media itself…
as soon as I get my transmission fixed. :slight_smile:

LOL I’ve got everything except what I need.

Sounds like my project. Which reminds me - have to go pick-up the parts that were ordered last night.

To be clear: one needs a LOT more than just the walnut media to do a walnut blast – especially if you want to do it right, and WITHOUT coating the entire back area with a fine layer of walnut… (mmm, walnut)

The actual media’s the easiest part – that’s $20 and an HF trip away.

And before @TLAR dings me on that one – I know, I know, not yummy at all. “Walnut blasting” doesn’t use walnuts – it uses walnut shells. Much less yummy, much more annoying. :slight_smile:

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Then again, eating walnuts doesn’t mean eating the shells. But who bothers to say “Walnut meats”.

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George,

No harm in your approach at all. The “suggested” tools used to media blast a BMW head/ports (per the context of this thread) can be purchased but most makers would consider them cost prohibitive ($1500ish last time i looked) The adapter to mate the media nozzle/vaccum attachment could probably be 3d printed, plus a shop vac, and a portable media blaster & and some makery, creativity, patience and you’ll be set!

George, (just curious here)
How do you plan on containing the media and residue from your car?
How do you plan to dispose of the residue - (Perhaps the tree hugging idiots in Austin that forced the pellet burning electric generating facility to be built a few years ago could use the residue - that is if that plant ever starts generating electricity)

Dry ice blast. That’s something else.

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I’ve got a model made up so I can 3d print an adapter, though I’m considering buying the factory adapter as it’s cast aluminum and $60. Draping off most of the engine bay for safety, though residue with the adapter is low to nearly nonexistent - just a matter of not using orders of magnitude more airflow at the blaster than the vacuum can pull.

Some folks sieve their spent walnut shell for reuse, and of course walnut shell itself is easily disposable and biodegradable. Since unlike with chem cleaning, with walnut blasting the carbon deposits stay solid I don’t know of any particular restrictions to their being disposed with regular waste - definitely interested if anyone knows otherwise so I can dispose of it properly.

There is a lot of that “solid” (may not be all “carbon” but most folks don’t want to inhale it when it was airborne) material stuck on the metal shop walls from the media blaster’s piss poor vacuum / filter set up…

Makes sense. I wasn’t planning to use the shop media blaster. (Wasn’t really sure that’d even be an option, the thing never looked all that conveniently mobile to me.) I picked up the little 20lb pressure blaster that was sitting around on the freebie shelf a while back and have cleaned it up a little and thrown on a regulator and dryer/filter (probably not super necessary in this case), was gonna use that. Long as I get a good seal out of the adapter I’m hoping that should take care of 99% of the airborne concerns. (Apparently a few folks swear by skipping the adapter altogether and just putting a thin blaster nozzle sized hole in a radiator hose, the flexibility of the hose providing the seal… Fascinating, though that may be a bit too risky for my taste.)