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Discussion Starter · #1 ·
CarThis is the big problem with most current GDI engines. Due to modern unburned hydrocarbon (UHC) regulations, vapors from the crankcase are usually vented into the intake stream in order to prevent oil droplets from escaping through the exhaust. In a port injection engine, these droplets are ‘washed off’ the neck of the intake valve by a relatively constant stream of gasoline droplets. In a GDI engine, the gasoline doesn’t touch intake side of the valve. As a result, the droplets have a tendency to bake onto the valve and significantly reduce performance. To add to this effect, many advanced GDI engines also include exhaust gas recirculation in order to lean out the combustion mixture and reduce in-cylinder temperatures for certain combustion modes (reducing NOx emissions). Since GDI combustion has the ability to produce far more soot than premixed combustion (port injection), the problem is magnified.

Carbon buildup on intake valves.

This is why i prefer a port injection engine like on my 2012 LX
I would like to hear your thoughts from 2014-2015 forte owners.
 

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Discussion Starter · #2 ·
Even more alarming is that these deposits can dislodge and damage other downstream components (turbochargers, catalytic converters, etc.). Manufacturers have added systems to capture these oil droplets and particulates, but no system is 100% effective. As a result, there are many disappointed early adopters with large repair bills. Even diesel engines haven’t been immune to these issues.
 

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Discussion Starter · #3 ·
This is the big problem with most current GDI engines. Due to modern unburned hydrocarbon (UHC) regulations, vapors from the crankcase are usually vented into the intake stream in order to prevent oil droplets from escaping through the exhaust. In a port injection engine, these droplets are ‘washed off’ the neck of the intake valve by a relatively constant stream of gasoline droplets. In a GDI engine, the gasoline doesn’t touch intake side of the valve. As a result, the droplets have a tendency to bake onto the valve and significantly reduce performance. To add to this effect, many advanced GDI engines also include exhaust gas recirculation in order to lean out the combustion mixture and reduce in-cylinder temperatures for certain combustion modes (reducing NOx emissions). Since GDI combustion has the ability to produce far more soot than premixed combustion (port injection), the problem is magnified.
 

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2016 Soul SX 2.0L - Caribbean Blue
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Posting the same info in two posts doesn't help your point, But that's why KIA recommends adding an additive if your not using TOP TIER fuel.

As KIA design engineer and build the engines and warranty them, and most of their lineup is now GDI, I think I'll stick to mine. (both engines on the Soul are now GDI).

Don't think a million+ owners of GDI engines will be returning them anytime soon.
 
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If that little bit of carbon bothers you install a water/meth injection system and problem solved.
 

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with the number of GDI's on the road, i think there would be something in the news or recall lists for something this big of an issue, if it in fact is this big of an issue.

i remember seeing where kia recommends using a cleaning additive... i put a full can of seafoam in the tank at each oil change.
 

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There have been a few issues with a couple BMW motors. Not a regular issue so no recall. More of a extra expense issue at maintenance time. There are a couple that are great motors with 0 complaint. Just do some homework when purchase time comes around. Know your products.
 

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Our 2007 VW is GDI and we haven't had any issues. This issue reminds me of the horrible valve wear issues we were going to have when lead was removed from gas. That didn't amount to anything either.
 

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Our 2007 VW is GDI and we haven't had any issues. This issue reminds me of the horrible valve wear issues we were going to have when lead was removed from gas. That didn't amount to anything either.
Ya better sell it and get a Steamer
 

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So much disinformation (again) sold as truth and fact. lol idiots. Want to know what the biggst issue for gunk on intake valves is on GDI engines? Improper maintenance and extreme OCI's. This allows the PCV to gunk up, forcing oil into the intake track where it sticks to everything, including the valve, allowing it to cause an issue.

So, once again, the "sky is falling" because people are lazy, cheap and stupid. Hyundai has been running GDI since 2010. GM since 2009. VW since 2007. With that many vehicles on the road for that long, we'd have heard about REAL issues long ago.
 

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I don't currently own any GDI engined vehicles because I'm too cheap to buy a new one. Not because I'm scared of them with an irrational, unfounded fear. I am to the point that no amount of stupidity astounds me. It just reaffirms that Idiocracy was a documentary and not fiction.
 

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