Carbon Build up on Direct Injection Engine (Intake Valves) AKA GDI Gasoline Direct Inection


Hi Paul from Deutsche Auto Parts, today we
are going to be going over Carbon build up on Direct Injection Engines and this is on
the intake values themselves. We are going to be including information about how it happens
and things that can be done to prevent it. [Intro: Deutsche Auto parts [DOY-chuh] 00:00:17-
00:00:22] The problem related to direct injection carbon
build up is a fairly new issue. This is a new issue mostly because direct injection
is becoming much more prevalent and widely used across all models, all vehicles. Specifically
the reason why it happens is because on a port injection engine the fuel injectors in
the intake manifold. So as the intake air comes in the fuel injector sprays on the back
of the intake valve. That will then help clean off any carbon build up coming back onto that
valve and then allow it to be burned in the combustion chamber. On the direct injection
the fuel chamber is inside the cylinder which means the fuel is sprayed inside the cylinder
and combusts there so as the intake air comes in the air flows directly over the back of
the intake valve and there is nothing in there cleaning it off.
The reason why the carbon build up happens on the valve and the reason why you do get
carbon coming in if you dont clean the valves is because of the PCV system. So the
PCV systems function is to take the blow that comes passed the piston during the combustion
process and vent it out of the crank case. Things that are in this would be things like
fuel vapors, oil vapors and any other things that would be unburned during the process
of combustion. That gets routed from a crank case up the engine and then out and then rerouted
into the intake manifold for emission purposes. As that comes into the intake manifold it
will then leave those deposits along the way mostly on the valves because it is the most
restrictive point of the intake track. So here we are going to show some examples
of carbon build up on valves. Our first example is of a 2.0T SSI VW engine
with 33,000 miles on it. This car as you can see has some mild build up starting but its
not terribly bad. It isnt going to cause any issue at all. All you are going to do
is have a little bit of a restriction in your air flow which can potentially affect fuel
mileage. This one isnt bad so its going to be a very small way.
Our next example is of the same 2.0T SI Engine on a different vehicle with 75,000 miles on
it. Now, as you can see this is pretty significant amount of buildup on this, its very visible
and its pretty bad. Now, once it gets to this point when you have significant build
up like this it has to be manually cleaned so what has to happen during that process
is the manifold has to be removed and the valves must be cleared by hand or by some
other mechanism. All right, so what can we do with the carbon
problem? As Ive mentioned before that car that has 75,000 miles on it, it has to be
manually cleaned. The options you have in that situation are only to remove the intake
manifold. Now how you clean it is going to very. A lot of times what they will do is
they will take a chemical soak it on the valve and then cleaning it with picks and scrappers
and things like that. Also another popular solution is soda blasting. This is a great
solution it will get it very clean, but also soda blasting makes a mess. Also another similar
solution to soda blasting is walnut blasting. So they take walnut shells, crushed walnut
shells, and they use it as a media to get rid of all the carbon in there. Again it will
make a pretty big mess and you have to have special tools for both of those processes.
If you allow the carbon build up to get bad enough that you are having issues related
to it, like, lets say you have 60,000 miles on it and there has been nothing done with
the vehicle you are probably getting to the point where you are going to need to clean
the carbon off. Now, the other option is okay how can we
prevent this? Carbon build up can be prevented in a few different ways. The most common one
and the most popular used in the automotive world and the affluent market is going to
be catch can. So what a catch can does is it takes your PCV system and reroutes your
PCV air flow to where it goes through a condensing car before it goes into the engine. And, what
that does is as it goes through that condensing can it will then condense those gases, all
the heavy stuff will sink to the bottom so it will be full of like oil type sludge, water,
fuel vapors, and a bunch of other nasty stuff. And here we will show you an example of what
it looks like when you are dumping out a catch can.
[Dumping Catch Can 00:05:14 00:05:18] So there are other options associated with
that is there are a lot of people who try to run some chemicals for example sea foam
and things like that. We dont have any claims that we know for certain that that
works. That is something that could potentially prevent it and also again just a disclaimer
a catch can will not solve your problem. It doesnt mean you will never have carbon
build up. What that means is that it will help slow down the process and so you will
catch a lot more of those contaminants before they get into your engine and get re-burned.
Some stuff is still going to get in there and you are still going to end up with carbon
it might last you another 10, 20, 30,000 miles. Other options associated with that stuff is
manufactures are starting to test with additional fuel injectors. Some of them like Toyota are
starting to put injectors in every single cylinder. So on a 4 cylinder engine you might
have 8 fuel injectors; 4 in the cylinder, 4 in the intake track. Some people are testing
with throttle by injectors. This way again we are getting fuel one those valves keeping
them clean. In the end at this point there is no perfect solution for this problem and
all you are trying to do is prevent it as much as you possibly can.
Thanks for watching, be sure to subscribe and leave any questions, ideas, or feedback
in the comments below.