Any GM Mechanics? Follow Up

[Steve@Advance]

On Saturday, I posted a question about my 2014 Silverado running poorly. No usual test points, nothing looks familiar...

Thanks for all the replies!

Hobo,NC got me on the right track. It is a GDI (gasoline direct injection) engine. Thanks for the link, it has some really crucial information every owner needs to know!

This is not good news! The GDI engines have a serious design flaw. It's not just GM using them either. The Ford Eco Boost engines are GDI, so are many other light trucks and passenger cars. It appears they are the coming thing for performance, emissions, and economy.

The problem is carbon deposits on the intake valves. Since the fuel is injected directly into the combustion chamber, there is no fuel in the air to keep the back side of the intake valve clean. Burning oil from the valve guide builds up, disrupts the air flow into the chamber causing poor performance. It eventually gets bad enough a large chunk falls off, holds the valve open or gets on top of the piston, damages/destroys the engine!!!

I suspect my truck is in the early stages, enough build up to cause poor performance. Being I just bought this truck last summer, I have no history on it. I bought it from a car lot, but it was a high end lot, not a tote the note. They seemed very conscientious about their sales. They volunteered to replace the windshield because of a tiny chip, replaced the missing spare tire, did a few other minor repairs. I noticed the oil was clean, full, and showed 100% on the life, so I assumed they had done an oil change. But what I don't know is, did they use the correct oil? Or what kind of condition the old oil was in before they changed it?

What I've done:

Today I changed the oil and filter. Went with Mobile 1, 0w-20, Dexos 1 approved, meets what the mfg requires. I cleaned the MAF sensor, cleaned the throttle body, (it wasn't bad), blew out the air filter.

Time will tell if anything improves.

I did find out the only way to check the fuel pressures is with a scanner, which I don't have. I'll either have to get one, or trade this off for an older model.

But, what I want to throw out there, probably many of you, like myself, have one of these engines and don't know it!

It is absolutely essential to use the correct oil, keep it full, and keep it changed!!! If using an oil change service, you will need to be sure they are using the correct oil, or buy your own oil, and watch them put it in!

Also, there is no snake oil cure for this! The owners manual cautions against using ANY oil additives. Fuel additives do no good since fuel never touches the back side of the valves.

The ONLY cure, and it is a temporary cure, is to pull the intake, reach in the intake port, and scrape the carbon out! Some say this needs to be done every 15,000 miles! WHAT A CROCK!!!

If this doesn't improve, anyone want to buy a like new, second owner, low mileage, late model unit with all new parts? Not cheap! LOL

 

[504]

I have a kit that Pennzoil handed out to shops years ago, that injects cleaner into the intake. All it is, is a hose and a valve,hook the hose to a full vacuum port put the hose in a bottle of fuel injector cleaner and slowly open the valve. In theory you would fog the motor till it dies, and let it set for a couple of hours to loosen the carbon. Back in the olden days, we would pour a cup of water in a cold running motor to clean the carbon from the piston tops.(Motor has to be cold or water on top of a hot piston = a cracked piston.)

 

[T in NE]

The egoboost shouldn't have this problem. No vacuum to pull the oil past the valve seals. Manifold is pressurized. Likely one of the reasons for going turbocharged.

 

[CaseChev]

This problem has been around at least since 1970 in a variety of makes and models by all manufacturers. You can obsess about it and try to get all sorts of social media support or just fix it. There are a variety of carbon cleaners that can be squirted/injected into the air intake that will fall on the back of the intake valves and soften the carbon. It will eventually fall off and be ingested into the engine and burned. You can even spray light amounts of water into the air intake, and it may soften and loosen it, but that treatment is primarily for carbon build-up on the tops of pistons vs. backside of valves. Several manufacturers even released walnut shell blasting techniques (BMW) to take the intake manifold off and blast the carbon off the back side of the valves. Welcome to the world of environmentally responsible clean engines.

 

[CaseChev]

Yes, this was another fix that actually worked quite well. This is not a new problem.

 

[Jon Hagen]

Good point on their being pressure fed turbocharged engines. This has me interested enough to put a vacuum gauge on my 3.5 Ecoboost to see how much load it takes for manifold pressure to go from vacuum to pressure.
I suspect an unloaded pickup will still pull a vacuum at cruising speed, but not nearly as much as a normally aspirated 5+L V8.

 

[CenTex Farmall]

I wouldn't believe you have that much oil getting by a positive seal on that new of an engine. With newer engines running roller everything I doubt there's a whole lot of oil up in the rocker boxes to begin with. Hopefully it's not that and the MAF cleaning will yield positive results.

They may have to tweak the oil formulation for these motors. IIRC turbine engine oil is designed to burn off with minimal coking if there's any leakage.

 

[Bob]

WHAT do roller lifters have to do with reduced rocker arm oiling???

 

[CenTex Farmall]

Nothing.

I used a generalization in reference to engineering efforts to cut friction where possible. Less boundary lubrication issues = less need for zinc type additives and heavier film oils.

 

[wilson ind]

Not going to help your engine, Just a thought from an older over active mind. LOL What about the valve rotation thing? Used to be an option as I recall , maybe standard on Allis Chalmers I think. Just a random thought.

 

[Hobo,NC]

I use BG products with good success.

Google bg products for gdi engines

You can fog the intake tract with cleaner. I have a good articular on GDI diagnostics IF I CAN find it .... Yes its somewhat new to the Independent repair trade as they are coming out of warranty the issues are starting to show up.

BG offers a lifetime warranty if you use there products some folks bite and others could care less. My son's soon to be wife has a 2014 Kia she can get the service for cost BUT both of them are the most fugal cheap arse couple you will ever meet in every fashion in there life... I should be proud but I would like some meat in my spaghetti sauce :lol: I know to tote my own tea to a meal invitation they drink water. If I ask for seconds they make you feel guilty LIKE I was gonna eat the left overs for lunch next week...


GDI is a hole new ballgame maintenance is top priority its not a issue to be a cheap arse on...

LInk GDI Vehicle list


https://drive.google.com/file/d/0B9gGQnPnPyTJcnNLblBJdDhEQkk/view

 

[Stephen Newell]

Are you sure the problem is with carbon deposits? With the emission control devices they put on vehicles today there are a bunch of different things could be causing similar symptoms. I had an old car two different mechanics said the motor needed an engine overhaul so the car sat for nearly a year. Then I found a good mechanic and had the car towed there and he fixed it for $65 bucks. It was just a wiring problem to some of the sensors.

 

[cuby]

I used to work for a IH dealer back in the early '60s and when the 460-560 tractors were common. A fella brought his farily new 560 gas in complaining that it was useing oil,head mechasnic took some Bon-Ami and let it suck through the carb in hopes to seal the rings. Cannt remember if this helped or not.

 

[Glenn F.]

...but he just scored the cylinders instead. Then it really did use oil.

Glenn F.

 

[Steve@Advance]

Hobo, I saw a Youtube video of the BG cleaner. It was a 2 part process, but it also required removing the intake.

Pour part 1 in the head (valve closed), let it sit for 2 hours, scrape it out, vacuum it out, pour in part 2, vacuum it out, repeat for each cylinder.

Didn't see a video about the fogging cleaner.

I would wonder about the efficiency of a one part fog, would it really work? And if the carbon was really bad, it could dislodge and damage the engine.

I'm hoping as these become more popular (or unpopular) there will be a solution, other than having to clean the valves!

Thanks!

 

[Steve@Advance]

Cen Tex, it did seem to run better this morning, seems to be worse in hot weather though. I have not scanned it for other problems, I need to do that before assuming the worse. But from what I'm seeing, it will happen eventually. I wonder what effect the intake valve canceling of the V4-V8 feature will have?

Thanks!

 

[pete 23]

I have done some reading up on the direct injection gasoline engines. It was supposed to be the cat's meow but unforeseen problems showed up. The build up under the intake valves has developed into a serious problem they are trying to overcome. They have some ideas they are working on to minimize the problem but no cure as of yet. It is absolutely nothing like the ordinary buildup we have seen ever since overhead valve engines were introduced. A cleaner will help get rid of carbon if added directly through the intake system, but nothing in the fuel will do any good. Several years ago Honda was very big in getting this engine out there but since then they have backed off I understand. Like all new designs, it take actual vehicles in the field for problems to show up .

 

[Steve@Advance]

Pete, you are absolutely right! I think they knew of the problem but put them out there anyway. Government pressure to increase mileage and reduce emissions, not wanting to be outdone by the competition. I haven't really seen the mfgs tooting their horn over this, just quietly putting them out there to the unsuspecting.

Thanks!

 

[Steve@Advance]

CaseChev, I'm seriously considering trading this off for a 2012, 2013. They didn't have GDI, was the end of the run for that style truck, had the bugs worked out, and something I can work on!

Thanks!

 

[CenTex Farmall]

I hate those "no code" maladies, when have an obvious problem and the computer is no help at all.

Did you ever find the fuel filter? I've had similar sounding problems due to a filter that was at or near capacity.

I don't think the 4/8 feature would have any effect on valve contamination since the valves are closed and not moving. I would say that the increased amount of mechanism for the feature would be more sensitive to contamination and sticking. I completely agree with using the specified oil and keeping it changed.

 

[CenTex Farmall]

I wonder if contamination from the pcv system has anything to do with the valve problem?

 

[dhermesc]

Sounds like a good time to use Seafoam through the intake a couple times a year to clean it out. A coworker has a Volkswagen Golf with the that issue. Took it to their shop at 40K expecting them to tear into the intake and heads to clean it out - instead they used some carb cleaner (I'm sure it was something more special than Gumout) through the intake (or possibly a vacuum line) and sent him home.



https://www.youtube.com/watch?v=I4pCmnRWtAM

 

[Steve@Advance]

Did you ever find the fuel filter?

No, I saw some generic diagrams, showed one in the tank.

I want to check the low pressure with a scan before going after the pump or filter. It has pressure transducers on the low and high side of the fuel system. That's why there are no test ports.

 

[David G]

If direct injection engines have this issue, why not Diesels?

 

[CenTex Farmall]

Diesel manifold operates close to atmospheric pressure. i.e. little or no vacuum to pull oil past guides.

Maybe some road diesels do have a throttle plate, my Farmall 400D has no throttle on the intake.

 

[Steve@Advance]

David, good question!

I suspect the intake valves run cooler because they have a lot more volume/velocity of air flowing over them.

 

[jimg.allentown]

By design, diesels do not use a throttle plate. Not even "road" diesels. Everything is controlled through and by the injection pump and injectors.

 

[jimg.allentown]

Just a few observations here....
Although the fuel is injected directly BEHIND the intake valve, this does NOT qualify as DIRECT injection in my book.

Start like this: if the fuel is injected BEHIND the valve, it is also being injected INTO THE AIRSTREAM. And as such, is going to be somewhat mixed with air in short order.

To my way of thinking, direct injection means DIRECTLY INTO THE COMBUSTION CHAMBER. Not behind a valve. To me this indicates INDIRECT injection. No matter how they play word games, DIRECT means DIRECT. Period.

So, you mean to tell me that 50 million dollars of engineering, research, and development cannot solve this problem?? That doesn't say much for GM's engineering staff.

A word about BG - as far as I am concerned, most of their stuff is your basic "mechanic in a can" snake oil.

There still is nothing in a can that can fix a broken part, put material back onto a scored crankshaft, repair a scored bore, fix a burned valve, or otherwise overhaul an engine without turning a single wrench. My opinion based on over 40 years of fixing the darn things.

 

[CenTex Farmall]

That's what I was thinking. I just haven't looked inside that many highway use diesels so I wasn't completely sure.

 

[Steve@Advance]

"I wonder if contamination from the pcv system has anything to do with the valve problem?"

Yes, it does contribute. So does EGR, if it has EGR, haven't determined that yet.

The inside of the throttle body was covered with a light oily film. That was coming from the crank case vent hoses off the top of each valve cover.

 

[ASEguy]

I was told at a recent clinic put on by Delphi the deposits are from PCV operation and will need to be done between 50,000 to 75,000 miles. Again this is what I was told. but I hear the carbon build-up is severe over time.

 

[pete 23]

A gasoline direct injection engine injects the fuel directly into the combustion chamber, same as a diesel. No mixing with air at valve before it enters cyl.

 

[David G]

That makes sense.

 

[Hobo,NC]

http://www.autoserviceprofessional....ssing-carbon-buildup-in-gdi-equipped-vehicles

 

[Hobo,NC]

I have a question... What is the oil Capacities. I have a 2015 in the shop (5.3) I can not locate the owners manual. I find info that states 8 ots and 8.5 what have you found that is the correct amount....

I drained 8 qt the dealer was charging him for 9 ot. I have the recites... Its always gaulded my arse that the manufactures have you go snip hunting for the capacities..

 

[jimg.allentown]

OK, I was going by what has been previously posted. After all of the other discussion in this thread, they apparently seem to think that fuel is injected BEHIND the intake valve causing carbon buildup. If it is truly direct injection, I fail to see how carbon buildup on the valve becomes a problem. So, all of the discussion about different products for removing that carbon seems irrelevant.

 

[Hobo,NC]

Think of your grill cooking grate ...

 

[GVSII]

(quoted from post at 19:01:31 06/06/16) OK, I was going by what has been previously posted. After all of the other discussion in this thread, they apparently seem to think that fuel is injected BEHIND the intake valve causing carbon buildup. If it is truly direct injection, I fail to see how carbon buildup on the valve becomes a problem. So, all of the discussion about different products for removing that carbon seems irrelevant.

As was stated above,the deposits are coming from the gases pulled from the crankcase by the PCV system.One way to clean the intake track and valves is by introducing a cleaning agent at the throttle body,PCV itself or through the power brake vacuum line.