Pontiac Solstice Forum banner

Direct Injection & Carbon Build Up Article & Vid

24K views 90 replies 20 participants last post by  CRiggleman 
#1 · (Edited)
OK, it's a Consumer Report article, but it's not a anti Direct Injection, as much as it's about concerns regarding long term DI effects. For those w/ADD skip to the vid below. ;) FYI; the 2.4 doesn't have DI.

Pros and Cons of Direct Injection Engines - Consumer Reports

Direct-injection engines improve performance and save fuel, but at a price
Cars with this technology might end up in the repair shop more frequently
Published: February 17, 2015 02:30 PM

It has been touted as the automotive holy grail, the ultimate marriage of better performance and greater fuel economy. It’s the direct-injection (DI) engine, the latest technology designed to squeeze more mpg out of cars. And it has actually been delivering results.

For example, the Mazda3’s combined fuel economy jumped from 28 mpg in 2010 to 32 mpg in 2012 in our testing of the new Skyactiv engine. Other automakers have been using direct injection to add horsepower—the Cadillac CTS, for example, gained 34 hp—without any sacrifice in fuel economy.

Though direct injection is currently seen mostly on luxury vehicles or on mainstream cars as a higher-trim option (priced anywhere from a few hundred dollars to a couple of thousand), it could soon be within the means of more drivers as costs continue to come down.

But those engines are also having reliability problems, something that automakers are trying to keep quiet.

Not surprisingly, a number of readers have asked us about direct injection. Take Anestis Halkidis of North Kingstown, R.I.:

“I have a 2006 VW GLI with the 2.0T FSI engine with direct injection,” he wrote. “At around 80,000 miles, I went to the VW dealer to diagnose a check-engine light. It turns out that the intake valves had to be cleaned due to carbon deposits that were causing drivability issues.”

When his dealer failed to offer free work or any compensation, Halkidis took his car to a local VW shop that cleaned the valves by blasting them with walnut shells. (Yes, walnut shells; it’s a method used by BMW.) The cost to Halkidis was about $400.

So what’s up with direct injection?
First, a primer on how it works: By injecting gas*oline at high pressure directly into the engine’s combustion chamber, direct injection more precisely measures fuel than conventional fuel-injection systems or old-time carburetors.

The result is more complete combustion and cooler cylinder temperatures that enable a higher compression ratio for greater efficiency and power. Engine technology supplier Bosch says that direct injection can return a 15 percent gain in fuel economy while boosting low-end torque as much as 50 percent.

Combining direct injection with other technologies—such as turbocharging—can deliver even greater gains in economy and performance. That in turn enables carmakers to use smaller displacement engines, resulting in an efficiency snowball effect. Many automakers are marketing DI as pro*viding fuel economy that’s almost as good as a hybrid’s, and with better performance—but without the $4,000 hybrid premium.

Although the breakthrough seems like a dream come true, an unwanted side effect has been emerging. Letter writers have complained to Consumer Reports and the National Highway Traffic Safety Administration (NHTSA) that over time DI can lead to clogged fuel systems and engine carbon buildup. The result can be engine hesitation and a loss of power—and the need for expensive repairs.

Some carmakers, including BMW and Kia, have issued technical service bulletins (TSBs) to their dealers recommending that drivers use only name-brand detergent gasoline—without ethanol additives—and that they periodically add a fuel-system cleaner when they refuel. (A TSB is an alert that the automaker sends to dealers to warn about ongoing problems with individual models and how to fix them. It may allow dealers to make repairs at little or no cost to the customer as a goodwill gesture.)

Other automakers have devised an engineering fix that works while the car is oper*ating. It involves modifying the engine to spray a small amount of fuel directly onto the valves to help keep them clean.

It’s important to note that not all cars with direct injection experience long-term problems. But if your engine stumbles more than it used to, or it suddenly lacks power, ask your dealer about it. A fix may be available, and you may not have to pay for it.


Below is a good vid of how DI works, why carbon builds up on the back of DI valves, explains the benefits of using an Oil Catch Can (shameless DDM plug), and how carbon will inevitable build up on the back of valves, and the various ($$$) methods used to clean it off.

 
See less See more
#4 ·
#49 · (Edited)
Hey Ghost, I'm watching the vids now, and it's talking about the turbo's going out after a induction service cleaning. Unfortunately, the vid doesn't really do a very good job of explaining the how the turbo can be damaged, other than mentioning higher heat. Could you expand on this please?

BTW, check out the vids Ghost posted, the guy has a tendency to ramble, but good info none the less.

At the very least FF to 5:53, there you will see examples of how much carbon can build up on the back of Direct Injection valves. Be scared, be very scared.
 
#6 ·
So unless you live in the peoples republic of Ca, why not just do it the way it was in the "old" days and just vent the head to atmosphere? Like, use a catch can but instead of feeding the output of the can back to the intake, let it vent to the atmosphere?
 
#8 ·
So isn't there a way to lightly mist (as in atomize) a solvent like seafoam in the intake to clean the valves? or would that crap out the turbo?
 
#11 ·
It's called Chevron...that's about the only thing that we can add to our fuel to try and help the issue. The Ford tech in my video attributes the build up of carbon on the PCV valve. So, maybe one of our "engineers" can come up with some sort of a filter to filter out the oil.....
 
#80 ·
Great info roxer. "Toyota/Lexus has issued a bulletin that instructs the dealer to install stronger valve springs to crush the deposit fracture."

Get that seat pressure up DI boys, you're gonna need it! Catch can will help baffle some of the oil vapors. Longer tubing will increase your condensation build up (chocolate milk shake)which gets sucked in on cold start BTW. External vacuum pump is the way to go.
 
#15 · (Edited)
QUOTE=spdygxp;1602393]I think a water/meth injection and a oil catch can would solve the problem[/QUOTE]

:agree: Proper crankcase pressure evacuation needs a vacuum source. The intake is a cheap but dirty way of doing it. An external metered vacuum pump to evacuate the vapors and pressure with a catch can is what I like to use. Belt drive or electric set ups are available.
 
#16 · (Edited)
A local shop that deals mostly in Cobalts charges $700 to do the walnut blast.
I did it myself for about $75 in parts and material including a new GM intake gasket and PCV valve.
It was a little intimidating first time doing it, but it went well, no issues. was about a 4hr job. Hardest part of the job was taking the intake manifold off. :cuss:

I used a $20 USB minicam to have a look inside through the brake booster vacuum port. Remove the hose and fitting. Wiggle the camera in until you find a view. Here is what I saw in cylinder #3 that made me know that it needed to be done.


I covered everything up expecting a big mess, but I spilled more walnut shell re-filling the hopper on the blaster than got spilled actually blasting.



I modified the blaster with a longer nozzle. And an old piece of rad hose fit the intake port and the vacuum perfectly. And of course the engine needs to be rotated for each cylinder so the intake valves are closed before pulling the trigger.



Here is the crushed walnut shell media. I bought a 30 lb bag but only used about 3 lbs. I used about 2 full hoppers per valve. It worked amazing.


IMHO the location of the PCV valve on this engine is just plain stupid.
I have relocated the PCV valve and where it draws from, and added catch cans on both sides of the venting system. At least the PCV system is serviceable now.
I am catching oil on the intake side. But because the car is away for the winter I still need more miles on it for evaluation as to how well that is working to help keep the intake cleaner.

I like the idea of completely separate vacuum source system. A few buddies run them on their race cars. hmmm!

BONUS.... I never really noticed a loss of performance prior to cleaning, Likely due to the gradual build up on the valves, but I sure notice an improvement afterwards. I'll probably do this service every winter now when the car gets put away.
 
#26 ·
A local shop that deals mostly in Cobalts charges $700 to do the walnut blast.
I did it myself for about $75 in parts and material including a new GM intake gasket and PCV valve.
It was a little intimidating first time doing it, but it went well, no issues. was about a 4hr job. Hardest part of the job was taking the intake manifold off. :cuss:

I used a $20 USB minicam to have a look inside through the brake booster vacuum port. Remove the hose and fitting. Wiggle the camera in until you find a view. Here is what I saw in cylinder #3 that made me know that it needed to be done.
Did the $75 include the blasting equipment? I am guessing you already had the compressor.
 
#17 ·
How many miles on your car WIFESGXP?????
 
#19 ·
Hey WifesGXP, if possible would you consider making a vid. Chances are I'd never attempt this myself, but just watching a vid of the procedure would help me understand what's all involved.
 
#28 · (Edited)
LOL, sorry I should have said IF you do it again.

BTW, has the car always used Tier 1 gasoline? The vid didn't mention gasoline quality (in our case GM recommends always using Tier 1 in the 2.0) but the vid did imply that carbon build up will occur regardless of what precautions are taken.
 
#25 ·
I have a Cadillac ATS with the Gen III LTG version of the 2.0L LNF engine. I got a letter from GM regarding the problem defined in ChopTop’s video and I’m taking it in next Monday for GM’s fix for the problem. The fix is installing colder heat range plugs and reprograming the ECM with a revised spark control calibration.

I interpret that as detuning the engine; I’ll let you know how bad it is when they get done. Since I have about a year left on the lease I really don’t care that much.

Jim
 
#31 ·
I'm wondering if that isn't the problem with mine misfiring occasionally during start up. Runs fine after it warms up and I clear the codes. So far cylinder 3 has been a constant when it throws codes. It's randomly thrown codes for all cylinders but that one has always been part of the bunch.
 
#32 ·
If you watch the vids I gave links too, (I know its for the Ford 2.0L ecoboost) that's where they are having issues too. On the number 2 and 3 cylinders are where they are getting their codes as well.
 
#34 ·
Ummm.... You know that on direct inject engines that the none of the liquid fuel touches the valves...right? That the fuel is not injected through the valves.... Therefore it really doesn't do too much other then clean the injectors. Thus the reason BG (or MOC or whatever your local dealer uses) Fuel Induction cleanings really don't work and actually harm your turbo.....
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top