Intake valve cleaning from carbon build up

[Husam]

Hello, I've been driving 2015 Gen. 3.8L and I came a cross the fact that it's a GDI based engine. The intake valves in such engines will be subject to more carbon build up by design, thus affecting the performance.

What's the recommended method of how to clean them up? A spray based method is not effective I guess in comparison to walnut blasting method. Have you tried them before? Results?

I don't really know.

Let me know guys.


Thank you,
Sam.

 

[carguy75]

I will just remove my intake manifold and let the valves soak in some type of carbon cleaner and a I will scrub the back of the valves with a brush the best I can. Hopefully the carbon buildup will not be too thick and can be dissolved with a cleaner with minor scrubbing.However, the best method of carbon removal would be walnut blasting.

I personally use only 93 octane and run my engine pretty hard often so hopefully I do not have a large build-up of carbon. I have read that direct injected engines that are ran hard usually have less carbon build-up than direct injected engines that have not been ran hard due to running low rpms most its life which are most engines since many directed engines are lightly used by most owners.

The heavy footed drivers seem to have the less carbon build-up due to pushing the engine to run in the upper rpms that prevents carbon from building up on the valves due to the valve excessive movement at higher rpms. However, my information is based more on the early VW/Audi/BMW engines that was very susceptible to carbon build-up which have a lot of information on the issue available online.

I believe that Hyundai uses the latest piezo-type fuel injectors which reduces the carbon build-up on our engines so excessive carbon buildup may not be an issue for our engines until well pass 100k miles.
Piezo Fuel Injectors Explained

Hand cleaning

Walnut Blasting

 

[hamed57]

I personally use only 93 octane and run my engine pretty hard often so hopefully I do not have a large build-up of carbon.

Hi, we are talking about direct injection engines. It means that the fuel does not pass through the intake. The fuel is directly injecting into the cylinder. So the fuel type and hard throttling has nothing to do with carbon build up removal. As a matter of fact the carbon build up on GDI engines is because of eliminating the fuel from passing through the intake. In older style engines fuel passes through intake manifold and cleans it.
In some newer designed GDI engines they added another fuel injector to the intake manifold to inject a little bit of fuel every now and then to prevent carbon build up.

 

[silberma]

You don't need high octane fuel for the Genesis. What Genesis does not tell you is that you should use tier 1 gasoline which have more detergents which will keep your engine clean. If you don't have access to tier 1 gas use an additive like Techron every few thousand miles to clean out your engine

 

[carguy75]

Hi, we are talking about direct injection engines. It means that the fuel does not pass through the intake. The fuel is directly injecting into the cylinder. So the fuel type and hard throttling has nothing to do with carbon build up removal. As a matter of fact the carbon build up on GDI engines is because of eliminating the fuel from passing through the intake. In older style engines fuel passes through intake manifold and cleans it.
In some newer designed GDI engines they added another fuel injector to the intake manifold to inject a little bit of fuel every now and then to prevent carbon build up.

Yes, I understand that we are talking about direct injection engines. 93 octane burns cleaner and also keep the high pressure fuel injectors clean which helps reduce carbon buildup on the valves. 93 octane or 91 octane allow the engine to go into the entire compression stroke which help with the combustion process by completely burning the fuel in the combustion chamber. Applying a hard throttle allows the engine to rev higher which moves the valves faster so that deposits are not able to stick to the valves as easy as when the engine rides along in low rpms.

But hey what do I know? I have owned about four direct injected engines before I bought my current direct injected Genesis 5.0 V8: VW 2.0T/3.6 VR6, KIA 2.0T, and GM 3.6 Flex fuel; so I have been researching what will work and will not work on preventing carbon build-up for about decade. However, if you believe that what i suggest will not work then just prepare to clean the carbon off your valves with the methods I posted.

 

[carguy75]

You don't need high octane fuel for the Genesis. What Genesis does not tell you is that you should use tier 1 gasoline which have more detergents which will keep your engine clean. If you don't have access to tier 1 gas use an additive like Techron every few thousand miles to clean out your engine

I have had this debate in about four different forum over the years from VW to GM in regards to what octane to use with a direct injected engine.

Regular octane is the bare minimum octane that these engine can use. When is using the bare minimum of anything the best method to use? High octane is not required, but it is the best fuel for the engine. Common sense if you know enough information about engines to debate about what to use.

This debate always stem from owners who wants to save a buck by only using regular octane fuel and then try to justify it as the best method due to some logic that premium gas has no additional benefits for direct injection engines because the owner manual states to use a minimum of 87 octane.

 

[hamed57]

I have had this debate in about four different forum over the years from VW to GM in regards to what octane to use with a direct injected engine.

Regular octane is the bare minimum octane that these engine can use. When is using the bare minimum of anything the best method to use? High octane is not required, but it is the best fuel for the engine. Common sense if you know enough information about engines to debate about what to use.

This debate always stem from owners who wants to save a buck by only using regular octane fuel and then try to justify it as the best method due to some logic that premium gas has no additional benefits for direct injection engines because the owner manual states to use a minimum of 87 octane.

I believe higher octane fuel is designed for higher compression engines to prevent knock. Genesis has a system to determine the type of the fuel you are using and set the variable engine comparison accordingly.
By using 87 octane fuel you do not compromise on engine durability or maintenance. The ECU will just adjust the compression of the engine to a lower setting. This way you lose a little bit of the horse power.
The engineers who designed this high tech engine know better than anybody else that 87 octane fuel won't cause any damage. Otherwise they just tell the customers to ONLY USE Premium Fuel like other high compression engines in the market.

 

[carguy75]

I believe higher octane fuel is designed for higher compression engines to prevent knock. Genesis has a system to determine the type of the fuel you are using and set the variable engine comparison accordingly.
By using 87 octane fuel you do not compromise on engine durability or maintenance. The ECU will just adjust the compression of the engine to a lower setting. This way you lose a little bit of the horse power.
The engineers who designed this high tech engine know better than anybody else that 87 octane fuel won't cause any damage. Otherwise they just tell the customers to ONLY USE Premium Fuel like other high compression engines in the market.

I will not argue this point yet again in another forum. If you believe that regular octane has no impact on carbon buildup or engine function so be it. It is your car so use whatever octane that make you happy. I personally will use only 93 octane in my Geneis 5.0 or any direct injected engine I own.

 

[Suburbazine]

Um. Wait wait wait...

The Genesis does not adjust DCR to compensate for octane. It changes the spark and injection maps to change the ignition point. This method is also less efficient so the engine loses power output.

If what you are saying was true, the Genesis would make an identical amount of power (albeit lower on the power band) by capitalizing on lower octane fuel's inherently higher burning speed. You'd also have other anomalies like modified exhaust frequencies and probably drone.

 

[hamed57]

Hello, I've been driving 2015 Gen. 3.8L and I came a cross the fact that it's a GDI based engine. The intake valves in such engines will be subject to more carbon build up by design, thus affecting the performance.

What's the recommended method of how to clean them up? A spray based method is not effective I guess in comparison to walnut blasting method. Have you tried them before? Results?

I don't really know.

Let me know guys.


Thank you,
Sam.

Hi my friend,

You need to educate yourself and get a basic understanding about how a GDI engine works. I found a very good video explaining the technology in a simple language. It helps a lot answering your questions. I love when somebody explains a scientific thing based on facts and science not something that you hear from a non educated mechanic.
In a simple word higher octane gas or fuel additives can help to have cleaner fuel injectors but they do not have nothing to do with the carbon build up.
The thing that help to reduce the carbon build up are: Using oil with less vapors, Using an oil catch can after PCV valve.
Please watch the video in the following link:

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[glennk]

Awesome vid!

 

[carguy75]

Very informative video!!! Catch cans attached to the PCV system have been the best solution among owners for years if done correctly like mentioned in the video. I have researched that carbon production is reduced by using higher octane fuel due to the fuel having more detergent and burning cleaner.

However, after looking at that very good presentation in the video it seems like the PCV system will just recycle oily blow-by film over the valves regardless of the fuel octane used. It seems that an good quality oil catch is the best method that may actually prevent carbon build-up on the valves in a direct injected engine. Using high quality oil that resist evaporation and top tier fuels also helps by minimizing the contamination source in my opinion.

All and all, it seems that carbon cleaning will just be a necessary service with direct injected engines regardless of using a catch can or not. The catch can will just extend the time for needing to perform the carbon service as well as using premium(top tier) fuel and engine oil with a very low evaporation rating.

Note: I have read articles like this that all states that premium fuel reduces carbon by burning cleaner and by have better quality detergent packages that reduces carbon production from non-burnt fuel during combustion that flows into the PCV system. Right or wrong makes sense to use premium gas in my direct injected engines over regular based on logic provided by the information I read on octane as it relates to direct injection.
Premium Fuel Futures

 

[2for1]

Can of Seafoam sucked into the intake through a vacuum hose. Let it sit for 15 minutes. Blow it all out with some high revs. Done!
Repeat often

 

[pmckechnie]

2for1 has the correct answer to this problem. The video did a good job of defining the problem but little about how to deal with the problem. A catch can will help, but not fix it. Good maintenance is the best answer. I will add one thing, that is after the Seafoam treatment, take the car out and from a dead stop (if possible), floor the accelerator and leave it there until you are going as fast as is safe. Do this a couple of times. The computers and transmission will keep the engine at high rpm safely. This will also help get some of the carbon off the pistons and exhaust valves.

 

[Gen127]

I use this product: CRC GDI IVD intake valve and turbo cleaner - every 7-9k miles.

 

[Acpantera]

Folks are forgetting the purpose of the pcv (positive crankcase ventilation)system, in every internal combustion engine there is a small amount of combustion from the cylinders that excape past the piston rings and into the crankcase, along with this blow by, the hot gasses vaporize a little bit of oil too. In the olden days, engines would be vented via a draft tube under the car. The gasses that fill the crankcase are a pollutant and re-burning them is the best way to solve the polluters.
When the gas was mixed in the intake manifold or injected outside the cylinder near the intake valves the gasoline kept the valve clean from crankcase fumes carbonizing on the relitively hot valve stems.
Direct fuel injection sprays the gasoline directly into the cylinder, no longer cleaning the intake valves, allowing crankcase fumes to bake onto the stems.
Catch cans can trap the oil vapors by essentially condensing them and keeping them from entering the intake tract.
Another way to reduce oily vapors in the intake is to use the highest quality synthetic you can get, it has better lubrication properties to keep piston rings sealing, and has a higher vaporizing temp so it doesn't burn off as ez.
Moral of the story.....
Change your oil often, at least at recommend intervals and don't be cheap when buying your oil AND gasoline.

 

[carguy75]

I use this product: CRC GDI IVD intake valve and turbo cleaner - every 7-9k miles.

Very good product. I will start spraying some of this in my throttle body or PCV port in the intake tract when the engine is running to help remove deposits every oil change(4k miles for me) and then spray an concentrated amount on the valves/chamber itself when I decide to remove the intake manifold at 100k miles to hopefully dissolve any large hard to remove carbon deposits that may need a bit of elbow grease to remove.
CRC also make a good video on carbon deposits and how their cleaner works as well direct injection overall. Very informative video that answers a lot of questions about direct injection engines and carbon build-up.

 

[arcman]

I really wonder as the the effectiveness of spray cleaners. Can't seem to find much in the way of independent reviews.

This looks like a better way to go. Think I'll get me one.

Engine oil separator in action: https://www.lsxmag.com/tech-stories/engine/catch-can-why-direct-injection-makes-them-a-must/

 

[Husam]

Very good product. I will start spraying some of this in my throttle body or PCV port in the intake tract when the engine is running to help remove deposits every oil change(4k miles for me) and then spray an concentrated amount on the valves/chamber itself when I decide to remove the intake manifold at 100k miles to hopefully dissolve any large hard to remove carbon deposits that may need a bit of elbow grease to remove.
CRC also make a good video on carbon deposits and how their cleaner works as well direct injection overall. Very informative video that answers a lot of questions about direct injection engines and carbon build-up.

I wonder if you could show me exactly how and where exactly you'd spray CRC cleaner passes the MAF sensors in Genesis g80. I couldn't find out how. Also, will that throw any error codes?

 

[Husam]

I use this product: CRC GDI IVD intake valve and turbo cleaner - every 7-9k miles.

I wonder if you could show me exactly how and where exactly you'd spray CRC cleaner passed the MAF sensors in Genesis g80. I couldn't find out how. Also, will that throw any error codes?