Engine Misfires - 2015 V8

[V8freak]

He probably just removed the intake manifold, soaked the valves with carbon cleaner, scrubbed the carbon off the valves and intake ports. That method would take about 3 hours. Either way, I am glad the cleaning worked out for you.

Ahh gotcha mb so . Anyway thanks for the help!

 

[Markymark]

Hi V8. First let me congratulate you on the successful repair. Glad the valve cleaning took care of the problem.
As for removing the valves...he absolutely did not! Had he done that you would have paid over $400 just for parts (valve cover seals, head gaskets, assorted incidentals). Two of the worlds fastest mechanics working together could not remove and reinstall and clean the intake valves in 3 1/2 hours. Period.

Hi,
I have been reading your comments and appreciate what you've said about the intake valve buildup issue. I am the new owner of a 2015 5.0, and only learnt about this issue a few days ago. I have no problems, but I think a lot of my driving is going to be to and from work (10 miles each way, suburban driving). I'm hopeful that I won't run into problems. I have owned numerous German cars and can turn a wrench, but am by no means a professional mechanic. I do not miss the sludgy B5 Audis and Passats.

So if I have the carbon buildup issue, how easy is it to remove the intake manifold and to clean out the valves with a liquid and some brushes? And is it really carbon per se? I would think that under conditions, it would be somewhat more akin to heavy, saturated hydrocarbons.
Thanks!

 

[DSXMachina]

Hi,
I have been reading your comments and appreciate what you've said about the intake valve buildup issue. I am the new owner of a 2015 5.0, and only learnt about this issue a few days ago. I have no problems, but I think a lot of my driving is going to be to and from work (10 miles each way, suburban driving). I'm hopeful that I won't run into problems. I have owned numerous German cars and can turn a wrench, but am by no means a professional mechanic. I do not miss the sludgy B5 Audis and Passats.

So if I have the carbon buildup issue, how easy is it to remove the intake manifold and to clean out the valves with a liquid and some brushes? And is it really carbon per se? I would think that under conditions, it would be somewhat more akin to heavy, saturated hydrocarbons.
Thanks!

Hi Markymark. I hear you about the Audi and Passat sludging issue. There were other cars marques with a similar problem, most notably Saab back a couple decades ago. "Sludging" cost a few engines, and a few million dollars for the OEM's on warranty repairs and goodwill
You're right, it isn't carbon in the coal sense, it is hardened, thickened condensed byproducts of combustion which are building up on the backs of the intake valves. Most of those byproducts originate in the gasoline. However whether there are any hydrocarbon molecules left I don't know. My gut feel is that there are none, because if there were they would act as a solvent and reduce buildup.
Nothing wrong with the intake valves, it's just that they cool down faster than the exhausts when the engine is shut down, and they have a direct pathway to the crankcase through the intake manifold and emissions plumbing.
An early sign of excessive deposits is roughness at idle. As the condition worsens the affected cylinders will run rich and can eventually misfire. Interestingly, the misfires can also occur in non-affected cylinders because the PCM will be drastically cutting back on injector pulse time in an effort to balance the reduced air intake. Some systems are smart enough to identify individual bad cylinders and adjust the air:fuel ratio just for the bad cylinders, but I don't know if the Tau engine can be controlled in that manner.
Don't lose sleep over it. Use Top Tier gasoline which early reports show helpful in reducing further deposits, and in reducing the amount of existing buildup. I think it is Shell which has the white paper research on this, but I haven't personally read it.
If you get to that point, and are handy with tools, the job isn't difficult, just a little time consuming. A pleasant Saturday would be the most for the average DIY'er. Lots of videos on the process of cleaning can be seen on YouTube, though we professionals tend to use corncob blasting. [WITH CLOSED INTAKE VALVES!]

 

[Phenix3st]

I’ve just joined but I’ve had massive up issues with this for years from new.Hyundai Canada has never been able to solve the issue. Mine has been in the shop over 30 times and still to this day the engine engine light will go on during some passing moves. The engineas been pulled from the car multiple times. I’ve also done the cleaning over 8 times now. The never ending nightmare continues. I’ll do a big post one of these days

 

[DSXMachina]

I’ve just joined but I’ve had massive up issues with this for years from new.Hyundai Canada has never been able to solve the issue. Mine has been in the shop over 30 times and still to this day the engine engine light will go on during some passing moves. The engineas been pulled from the car multiple times. I’ve also done the cleaning over 8 times now. The never ending nightmare continues. I’ll do a big post one of these days

pulled?
Do you have a list of any and all codes which the dealership pulled? Which engine are we talking?

 

[Phenix3st]

pulled?
Do you have a list of any and all codes which the dealership pulled? Which engine are we talking?

Yes, the engine was pulled from the car along with the transmissionAnd drive train.

Sorry for the shit spelling and spacing. The typing on the iPhone and iPad here is messing things up.

I’ve always had an issue with cylinder 8 getting a miss fire under loaded or passing situations. There are also a few other cylinders That like to pop up from time to time.

 

[Cudhoo]

Your symptoms sound like the one I had. Mine was the Oil Control Valve. See here. My V8 is Sick

Hi friend. Any suggestions for me. Seems to shutter and misfire. I don't get any check engine lights but it seems like it's struggling for fuel every now and then it will stall and it takes a little bit for it to turn over before it'll actually start as if it's not too fuel. (2015 V8 ultimate - random miss fire, no codes)

any help would be appreciated