Carboned Intake Valves

[Rygrego]

You must be new to engine tech?
When DI came around valves started carboning up b/c the FUEL injector was no longer located behind the valve to keep it clean. Top Tier + has everything to do with helping with fuel & DI engine carbon issues (hence my suggestion you quoted to use TT+ in DI engines).
Please study up on the subject.

The carbon on the manifold side of the valves is caused by pcv mist not being washed due to the lack of fuel washing it off during intake.

You must be new to engine tech?
When DI came around valves started carboning up b/c the FUEL injector was no longer located behind the valve to keep it clean. Top Tier + has everything to do with helping with fuel & DI engine carbon issues (hence my suggestion you quoted to use TT+ in DI engines).
Please study up on the subject.

No it doesn’t. The fuel never touches the affected parts of the valves. The carbon buildup is caused by pcv vapors not being washed by a port injector. I believe it’s you that needs the schooling.

 

[97prizm]

Full time port fuel injection is the best way to keep the valves clean.

Don't buy a car with GDI, AFM, or VVT. Just say no to unnecessary complexity.

E D I T

I hope this thread gets moved to the Mechanical/Maintenance Forum.

I didn't know I was in the PCMO Forum.

I take pride for not posting there.

Variable valve timing is a good thing.

 

[fantastic]

The carbon on the manifold side of the valves is caused by pcv mist not being washed due to the lack of fuel washing it off during intake.

No it doesn’t. The fuel never touches the affected parts of the valves. The carbon buildup is caused by pcv vapors not being washed by a port injector. I believe it’s you that needs the schooling.

I think there's a misunderstanding...

1. You are talking about how carbon is created.
2. I'm talking about what OP can use to help or limit it from getting out of control by using Top Tier + fuel.

 

[fantastic]

Is this referring to the ASTM D6201 test? If so, that’s using a mid 90s MPI Ford Ranger and isn’t relevant for a GDI engine.
Or is there a newer IVD test on a 2.3 EB GDI engine?

The D6201 test is the basis for my point. The goal here is to show that Top Tier is not just a "marketing scheme," as some have implied. Regardless of its age, the test provides validated standards and real-world data confirming that even the original Top Tier requirements were effective at cleaning intake valves.

 

[jsean]

It is the D6201. The point being proof it's not a "Scheme", as was implied, & actually has testing standards old or not there are actual real life results that show proof of even the old Top Tier standard cleaned valves up.

Fair enough. But it’s for a spark injection / MPI engine. Different beast than a GDI engine. Top tier + gasoline will certainly help with cleaning the DI injectors. But I think folks have had good luck running Techron additive / Redline Si-1 and keeping their injectors clean. None of that is going to meaningfully impact or control IVDs.

 

[fantastic]

Fair enough. But it’s for a spark injection / MPI engine. Different beast than a GDI engine. Top tier + gasoline will certainly help with cleaning the DI injectors. But I think folks have had good luck running Techron additive / Redline Si-1 and keeping their injectors clean. None of that is going to meaningfully impact or control IVDs.

That is a fair point, but I would argue that cleaner combustion via well-maintained injectors leads to fewer overall engine emissions, which in turn reduces the severity of the soot and vapors passing through the PCV system.

It is also worth noting that the current Top Tier Plus (TT+) standards go well beyond the older D6201 testing. They now incorporate specific testing on GDI platforms, such as the GM 2.0L, to address modern carbon concerns. That is why I believe bringing TT+ into this discussion is relevant—it is actively being evaluated against the specific challenges presented by GDI technology.