GDI engine sticking valves?

Does holding a piece of paper against the muffler really indicate sticking valves?

The paper is flapping back and forth on each bank/muffler.

Engine code was cylinder 8 misfire so I swapped coils same result.
I then swapped plugs and coils (8 & 1) and no misfire code.
Engine still idles like crap and will sometimes shut down.

Check engine light is on and the new code is P0109.

It's a 2014 Equus 5.0 Tau motor with 165k miles.
I don't believe the intake system has ever been "serviced" cleaned.

I went thru all the grounding connections and cleaned them up hoping it was that simple.
One grounding point in the engine bay by the ECU has several connections to it. It was rusty and after cleaning that up it obviously did sweet fack all to cure the issue.

I had a shop replace the starter motor a few weeks ago, car ran fine for the 3 mile trip home then shuddered and stalled as I backed into the driveway.

Hellip!!

 

I have a 2012 genesis 3.8 sedan and I believe they are the same generation.

Have you been regularly running intake valve cleaner in this engine? It requires bringing engine up to temp, spraying it into intake manifold past your mass airflow sensor in bursts then letting it sit then running the snot out of it to break off the carbon deposits.

I do recommend a high quality oil like royal purple or better and keep the oil level at full.

I get some valve clatter now n then but it normally goes away if I make sure the oil level is full then go punch the throttle a few times.

 

I haven't.
I just picked this car up a few months ago.
Throttle plate is really grimy.
I've had several Equus models before and never encountered this.

Any idea where to spray into the intake?
I see two sensors at the rear of the intake....I think one is the manifold pressure sensor and the other is a temperature sensor .
Would they become damaged if I spray the cleaner thru the throttle plate.?

 

You need one more thing for that cylinder to fire that you haven't mentioned. Check the injectors....

 

You will need to find a spot past the mass air flow. Let me see if i can get a pic. Where my finger is the location of mass air flow. Past that.

Are you hearing valve clatter when you start the engine cold?

 

Not sure. I do hear the high pressure fuel pumps clacking.
Seems like they've always been quite loud on all the other Equus I've had. They even have a sound deadening insulator over them.

 

I'd find it hard to believe a 2014 never had a intake valve clean done. Especially with that amount of miles. I would do 2 things....clear your p0109 code then run some royal purple fuel injector cleaner in your fuel. After that I'd do a CRC intake valve cleaner.

See if your P code shows pending....check it every time you drive after putting in the injector cleaner.

I'm curious...do you know of the any of mtx history?

 

Anyone looked to see if that CRC intake valve cleaner actually works? I have a 3.5 Ecoboost with 158k that could probably use a cleaning. Still runs great. Debating pulling manifold and doing a walnut blast cleaning. Rather not if the CRC stuff actually works.

 

Can't believe no one has said.. seafoam that bitch..

 

And no the paper on the exhaust means nothing

 

I didn't borescope the valves afterwards but the top end valve clatter ended immediately after crc cleaning.

 

Old School Cadillac tech here. Didn't bother with that wierd shit. We made "salad oil". I forgot if it was one part water and two parts ATF or two parts water and one part ATF. Worked great when a piece of carbon broke off in a 472 cylinder and caused all sorts of scary noises. Pour a dose into a hot motor until it stalled, let it soak for 20-30 minutes, then fire up and rev the piss out of it. The fun part used to be when the wind was right, a huge cloud would drift over to the McDonalds next door!

 

Marvels mystery oil in the gas for your injectors too. I use it in my chevy.

 

Gawd darn it. I bailed to 3 stores and nobody had it in stock.
napa had Soltec brand at $46 for a spray can and fuel tank additive.

The car's been sitting for several months. Could the fuel have gone bad, causing this shizz?

 

All the more reason to clean it out

 

This is crazy. I leave for an hour or so, start the motor to bring it to temperature and it now just cranks and cranks.
Once it stops cranking the cooling fan comes on and stays on for 30 seconds or so.

Started fine all morning until I returned from the store. I drove a different vehicle to the stores.

O2 sensor & cylinders 1,3,5,7 now misfire codes.
Putting the battery on a charger for now.

 

You leave something unplugged?

 

All these new Direct Injection engines have build up on the valves. Oil vapor goes through the intake due to the PCV valve and there is no fuel in there to clean it. So the oil gets hot and burns onto the valves, seats, etc. This pic is one of my intake valves after 90,000 miles with no cleaning. I had to take the top end apart to replace lifters and such. I cleaned them and re installed and added a catch can. The amount of oil that can gets every couple months is eye opening.

I would recommend a catch can and cleaning for all Direct Injection engines.

 

It fired up fine just before I headed to the parts stores

 

I saw there is new motor oils on the market to help address this, too.