Thoughts on direct injection?

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Originally Posted By: Quattro Pete
Originally Posted By: itguy08
Your valves don't care if they are dirty or clean (within reason). Your engine doesn't either as it will adjust the mixture so you are always running well.

Tell it to all those DI owners whose engines run like [censored], their CEL light is on, and they have to go in for periodic cleaning.


You must have missed the part where I said WITHIN REASON...

I have no doubts mine have deposits. They are within reason and the engines run fine.

Early designs - looking at you VW/Audi/BMW did have issues. Latter designs seem to be less problematic.
 
Originally Posted By: Quattro Pete
Originally Posted By: itguy08
Your valves don't care if they are dirty or clean (within reason). Your engine doesn't either as it will adjust the mixture so you are always running well.

Tell it to all those DI owners whose engines run like [censored], their CEL light is on, and they have to go in for periodic cleaning.


I think biggest problem is with I gen VW/Audi TFSI and FSI engines. Choice of oil by VW and OCI did not help too.
 
It's just going to take some time and miles to sort out DI.

Smog control devices and system had a rough start.

FI has a long slow start with problems, too.

Automatic transmissions had a long slow start with problems, too.

Air conditioning had a long slow start with problems, to.

....and on and on and on.

Today's automobiles are a marvelous example of development.
Imagine what it would take to make a car from scratch, every single part, no standards, nothing off the shelf and no copying or reverse engineering, locked away somewhere with all the tools and materials needed at hand.
 
One thing that will get things better is when the OEM's figure out that they need to filter the dirty side of the PCV system to keep oil and particulates from being ingested into the intake and getting on the valves. Port injection took care of much of that. The small vehicle OEM's haven't quite figured this out. The commercial heavy diesel OEM's knew it right out of the gate and provided filtration to capture oil and particulates when they started putting on CCV systems on their diesels in 2007.

Maybe some of the auto/pickup OEM's might want to give the folks over at the commercial truck engine makers a call and get some advice. Until then, some of us have already installed some form of filtration for the PCV line to capture the gunk that goes thru there to the intake.
 
Many oem already have separators and devices designed to reduce oil vapors in the intake.

Millions upon millions of cars and trucks world wide have no catch can or any device in their PCV except the ubiquitous one way valve. They run just fine.

I wonder how that happens...
 
My 2007 Mazda with DI was running great when I sold it with ~ 80,000 miles and Mazda said they now have a solution for long term intake valve crud. Their solution was to keep the intake valve hot. I now have a 2014 Mazda CX5 and expect no issues in that area for 125,000 + miles. I just will enjoy driving the vehicle. Ed
 
Originally Posted By: SteveSRT8
Many oem already have separators and devices designed to reduce oil vapors in the intake.

Millions upon millions of cars and trucks world wide have no catch can or any device in their PCV except the ubiquitous one way valve. They run just fine.

I wonder how that happens...


Guess I really have no dog in that hunt anyway. I didn't want the AFM, DI type of motors that GM is kicking out for their 1500 series pickups so I got a 2015 2500 6.0L that has none of this stuff. I like others to be guinea pigs while the OEM works out the bugs in their motors. I do know that none of the GM motors with DI have any kind of filtration on the PCV dirty side. And from a lot of scope pictures I have seen of intake valves on them after being used for only a short while, I am not game for buying one of those motors. Each person can make their own determination.
 
I think Eddie nailed it....just enjoy driving the vehicle. I think sometimes we think way too much when it comes to maintenance on this forum. But hey, it's what we do!!!! DI is the "new" thing and eventually it's going to happen like carbs to fuel injection. Embrace.
 
Never heard of any GM DI engines needing carbon work but Audi had a huge issue early on. I can only tell you that I have a 2008 Cadillac 3.6DI with 101k miles and my mom has the same car with 86k miles and we each have NO issues.
 
To be fair, gunk forming in the throttles of cars by all makes and models has caused a decent number of drivability issues well known to dealers/manufacturers. Almost every manufacturer has a cleaner or kit for cleaning the mess left by the PCV system.

Some cars became notorious for evacuating their entire oil capacity at high rpm through their PCV systems.

Others have undergone multiple revisions to the valve cover and PCV system to end known issues of throttle fouling.

PCV system has not been a death sentence to automobiles, but they've certainly introduced a fair share of issues.
 
There is the increased production of soot particulate in D.I engines . Don't know if that's showing up in oil or emissions.
 
Originally Posted By: badtlc
Originally Posted By: Miller88
I don't think lean burn is allowed here in the US. They have to run richer to keep the catalyst up to temp.


DI engines in the USA use an "ultra lean" or stratified burn mode. It actually reduces emissions.


Are you sure? My understanding is that we do not because our sulphur levels don't allow it as it along with the higher exhaust temps would poison the cats too quickly preventing the removal of NOX. US car run richer to keep exhaust temps lower so NOX is lower.
 
Originally Posted By: eddy21
There is the increased production of soot particulate in D.I engines . Don't know if that's showing up in oil or emissions.


Emissions and it's worse than diesels in some ways.
 
Originally Posted By: BMWTurboDzl
Originally Posted By: badtlc
Originally Posted By: Miller88
I don't think lean burn is allowed here in the US. They have to run richer to keep the catalyst up to temp.


DI engines in the USA use an "ultra lean" or stratified burn mode. It actually reduces emissions.


Are you sure? My understanding is that we do not because our sulphur levels don't allow it as it along with the higher exhaust temps would poison the cats too quickly preventing the removal of NOX. US car run richer to keep exhaust temps lower so NOX is lower.


Correct, this is also reason why you get fuel in the oil. Personally I would avoid DI until you guys get low sulphur petrol.
 
Originally Posted By: chrisri
Personally I would avoid DI until you guys get low sulphur petrol.

It's not just the sulphur issue. It's our emissions standards that would need to change.
 
Originally Posted By: BMWTurboDzl
Originally Posted By: badtlc
Originally Posted By: Miller88
I don't think lean burn is allowed here in the US. They have to run richer to keep the catalyst up to temp.


DI engines in the USA use an "ultra lean" or stratified burn mode. It actually reduces emissions.


Are you sure? My understanding is that we do not because our sulphur levels don't allow it as it along with the higher exhaust temps would poison the cats too quickly preventing the removal of NOX. US car run richer to keep exhaust temps lower so NOX is lower.


Yes. I'm 100% positive. Feel free to google it yourself.
 
Throw MINI into your list of troubled engines. I had one.

I wonder what has become of Toyota's plan to use two systems concurrently? Normally the engine is a DI, but at certain intervals it switches to the legacy injection system to wash down the valves.
 
Originally Posted By: crw
Throw MINI into your list of troubled engines. I had one.

I wonder what has become of Toyota's plan to use two systems concurrently? Normally the engine is a DI, but at certain intervals it switches to the legacy injection system to wash down the valves.


It is NOT for washing down the valves.
 
^^^Exactly. Toyota told car and Driver that the system is designed to eliminate some part throttle cylinder filling issues that are common to DI engines...
 
Originally Posted By: badtlc
It is NOT for washing down the valves.

But it does have the side benefit of washing down the valves.
 
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