92K miles on my M56 and have run two different chemical cleaners through the engine in the past 20K miles. Looks like the cleaner only reached the rear 4 cylinders. Pics are in order 1 through 8. I can only imagine what they would look like on an untouched 90K mile engine.

These are the intake valves? I would have thought these are the exhaust valves.

That is freakin crazy the amount of carbon build up on them. I mean it's got to be affecting performance. Man... I've got to go out and buy an engine detergent before I change oil. Wow... Thanks for sharing those pictures.

No engine detergent will help that issue, PostalsQ.

It is specific to the Direct Injected 5.6L models. The 3.7L models have port injection which keeps the intake valves clean thanks to fuel being sprayed onto them which contains detergents.

This is common of all DI engines. Some are worse than others.

ArmedAviator wrote:No engine detergent will help that issue, PostalsQ.

It is specific to the Direct Injected 5.6L models. The 3.7L models have port injection which keeps the intake valves clean thanks to fuel being sprayed onto them which contains detergents.

This is common of all DI engines. Some are worse than others.

Yeah that's bananas. No wonder why our M56's feel like pigs when the weather gets hot...they probably all look like this or worse! WTH?

So, how does one go about cleaning this up without removing each part and cleaning by hand? Does the dealer cleaner work better than the ones you can buy at walmart, etc?

Also, how were these pics taken? I run a cleaner much more regular (every 4-5k) and have been since I got the car with 42kmi on it...I wonder what mine look like at 89kmi. Better or worse than this. I've also been UpRev'ed for the last 10-15k or so, so I'm wondering if 'correcting' the AFR would help...I'm assuming it would?

The 3.7 as regular port fuel injection. Detergents in top tier fuel like Chevron or Shell will help keep the valves clean along with a regular dose of something like Techron.

Fuel pour in additives will do nothing for the intake valves on a DI 5.6. The cleaners I ran were intake system cleaners that you run into the engine through the PCV system or other vacuum source on the intake manifold. I used the T fitting between the throttle bodies that the purge solenoid is hooked to under the intake cover.

My pictures were taken straight down the intake port s with the intake manifold removed from the engine. I am using a combination of Carb Cleaner, a toothbrush, a small dental pick, and crushed walnut shell media blasting to clean the carbon. I have 3 intake ports mostly clean. It is nasty and time consuming. Then again it is practically free horsepower to me and should result in a more efficient tunning engine.





To prevent this from building back up I think I am going to do two different things. First I am going to install a PCV catch can. Then I am also going to install a water/methanol injection system that activates at WOT. Methanol is a very good cleaner and the water turns to steam and will keep the combustion chamber much cleaner. It also raises the octane of the fuel keeping the engine from detonating. I will put it on a TPS window switch that enables when the throttle bodies open fully. Just need to find a pair of sprayers. Tank and Pump will end up in the trunk. Probably use a 2.5 gallon sprayer as those already have a suitable 12v on demand pump on them.

I use Seafoam directly into the manifold every 30kmi (vacuum source). So mine might be a tiny bit cleaner but I'm curious to see your final results. How hard was it to remove the manifold?

Ilya wrote:I use Seafoam directly into the manifold every 30kmi (vacuum source). So mine might be a tiny bit cleaner but I'm curious to see your final results. How hard was it to remove the manifold?

Not bad other than the stupid wiring harness bracket on the passenger side that also holds the Evap filter.

Took me maybe 1 hour taking my time. Lost maybe 1 cup full of coolant.

Some of the Diesel guys I hang around with swear by the occasional Seafoam treatments. And of course there are those who have good luck with water/methanol. Those are two great options IMO. Maybe look into a Snow Performance system. The last pictures look so much better.

Need to revise my tune a bit now. . It is running even richer than it was before. Pulling a good bit more air across the MAF. Gotta say this car has never had power like this since I have owned it. I did not lay into it until I was already rolling and it still broke the 275/40R20s on the acck loose.

https://www.youtube.com/watch?v=KZcJDX2lWEY

I rescaled the compensation table to go to 7,000 rpm. WOT is now in the 12.2-12.4:1 range from 3,000-7,000 rpm. I seem to be maxing out what the MAFS are programmed to read. I am seeing a steady 345.59 gm/sec across a spread of 1,000 rpm, 6,000-7,000. Can always add fuel via the compensation table but seems weird that there is a limit to the MAF reading set so low hidden somewhere in the tuning. The MAF voltage increases but the MAF flow reading flat lines. The calculated load percentage drops below 100% when the MAF reading maxes out by keeping the Base fuel numbers from rising. I need to look at the load scaling map and get that to max out at 100% for the transmissions sake.

Oh and its faster than a moded turbo Evo from a good roll, but he did get me when I tagged the rev limiter on the 1-2 from a 20 roll. I was cutouts closed and did not feel the need to draw even more attention.

The hesitation in my car is 100% without a doubt temperature related. I got it up over 210°F oil temp and that nasty hesitation that shows up in the summer time came right back. Coolant got up to 190°F with the fans at 100% duty cycle. When the car is cooler though it runs alot smoother and has better response. I think a good thermostatic oil cooler setup would help tremendously. My oil temps shot up 20°F after 2 WOT 0-70 mph runs on a 75°F day. Mileage is up as well. I cruised about 20 miles on the highway at 65-70 mph with the fuel economy display pegged above 30 mpg.

DFW2011M56S wrote:I rescaled the compensation table to go to 7,000 rpm. WOT is now in the 12.2-12.4:1 range from 3,000-7,000 rpm. I seem to be maxing out what the MAFS are programmed to read. I am seeing a steady 345.59 gm/sec across a spread of 1,000 rpm, 6,000-7,000. Can always add fuel via the compensation table but seems weird that there is a limit to the MAF reading set so low hidden somewhere in the tuning. The MAF voltage increases but the MAF flow reading flat lines. The calculated load percentage drops below 100% when the MAF reading maxes out by keeping the Base fuel numbers from rising. I need to look at the load scaling map and get that to max out at 100% for the transmissions sake.

Oh and its faster than a moded turbo Evo from a good roll, but he did get me when I tagged the rev limiter on the 1-2 from a 20 roll. I was cutouts closed and did not feel the need to draw even more attention.

The hesitation in my car is 100% without a doubt temperature related. I got it up over 210°F oil temp and that nasty hesitation that shows up in the summer time came right back. Coolant got up to 190°F with the fans at 100% duty cycle. When the car is cooler though it runs alot smoother and has better response. I think a good thermostatic oil cooler setup would help tremendously. My oil temps shot up 20°F after 2 WOT 0-70 mph runs on a 75°F day. Mileage is up as well. I cruised about 20 miles on the highway at 65-70 mph with the fuel economy display pegged above 30 mpg.

This is all so crazy lol. Write a good howto document so I can send it to my tuner and have him look at my maps. I probably won't go through the task of cleaning the IM but at least the other stuff.

So would a GTR MAF be better suited for you? Maybe some redline water wetter treatment in The radiator? Would a hair cooler thermostat work? I like the oil cooler idea. And is the radiator just to small for the 5.6? Would a Mishimoto be better suited? BTW, EGT's really go down on diesels with Snow performance water/methanol. That might be the ticket for you 5.6 guys.

PostalsQ wrote:So would a GTR MAF be better suited for you? Maybe some redline water wetter treatment in The radiator? Would a hair cooler thermostat work? I like the oil cooler idea. And is the radiator just to small for the 5.6? Would a Mishimoto be better suited? BTW, EGT's really go down on diesels with Snow performance water/methanol. That might be the ticket for you 5.6 guys.

Honestly I do not see it maxing the MAF itself out. It is hitting some limit in the ECU code that is hard programed into it as a maximum airflow value.

As for the thermostat I am already running a Nismo thermostat that starts to open at 149°F and have a Nismo 19 psi high pressure cap.

It was 75°F and humid on my way home tonight and the engine got to 189°F with the A/C on. The fans were on at 100% duty cycle. When I pulled into the driveway. The radiator seems to be flowing fine. I may try the water wetter but in my experience it does very little other than cost you money. The engine seems to stay cool as far as water temp goes. Its the oil that gets hot atleast on my car. The stock oil cooler also dumps its heat into the cooling system.

The reason I mention the GTR MAF is I've been reading guys using it in boosted applications which leads me to believe it's an upgrade and allows for better tuning somehow. Funny water wetter comment. LOL. But I hear ya. So water cooling seems good. Just better oil cooling needed. Well. I see a nice big oil cooler in your future. And jealous of your weather. Damn weather has been in the high 20's in the AM here.

They look like that with 10,000mi on them too. Infiniti says it's normal.

BlackCat81 wrote:They look like that with 10,000mi on them too. Infiniti says it's normal.

That is Infiniti side stepping the built-in flaw they created in this engine. The VK56 has never had enough baffling in the PCV system and they all burn oil through the PCV because of it.

I had 2 cylinders that had valves that were not even fully seating because of the carbon buildup on them. The amount of carbon in the ports, bowls and valves was killing performance in my car.

I am up 2 mpg this week compared to last week. I am averaging 18 mpg in-town despite multiple romps to 6,500+ daily.

Also between adjusting the AFR and cleaning the ports and valves the black soot on my exhaust tips and grey haze when I lay into it have been minimized. My WOT air/fuel ratio target is 12.46:1 and I am holding it fairly consistently.

DFW2011M56S wrote:

BlackCat81 wrote:They look like that with 10,000mi on them too. Infiniti says it's normal.

That is Infiniti side stepping the built-in flaw they created in this engine. The VK56 has never had enough baffling in the PCV system and they all burn oil through the PCV because of it.

I had 2 cylinders that had valves that were not even fully seating because of the carbon buildup on them. The amount of carbon in the ports, bowls and valves was killing performance in my car.

I am up 2 mpg this week compared to last week. I am averaging 18 mpg in-town despite multiple romps to 6,500+ daily.

Also between adjusting the AFR and cleaning the ports and valves the black soot on my exhaust tips and grey haze when I lay into it have been minimized. My WOT air/fuel ratio target is 12.46:1 and I am holding it fairly consistently.

Wanna trade manifolds? lol.

Ilya wrote:

DFW2011M56S wrote:
That is Infiniti side stepping the built-in flaw they created in this engine. The VK56 has never had enough baffling in the PCV system and they all burn oil through the PCV because of it.

I had 2 cylinders that had valves that were not even fully seating because of the carbon buildup on them. The amount of carbon in the ports, bowls and valves was killing performance in my car.

I am up 2 mpg this week compared to last week. I am averaging 18 mpg in-town despite multiple romps to 6,500+ daily.

Also between adjusting the AFR and cleaning the ports and valves the black soot on my exhaust tips and grey haze when I lay into it have been minimized. My WOT air/fuel ratio target is 12.46:1 and I am holding it fairly consistently.

Wanna trade manifolds? lol.

Wouldn't help you. The buildup is in the heads.

Oil catch can do anything to help the PCV system?

DFW2011M56S wrote:

Ilya wrote:
Wanna trade manifolds? lol.

Wouldn't help you. The buildup is in the heads.

lol, fail. That's what I meant but was joking, that's way too much work for me so glad you're seeing results.

DFW2011M56S wrote:The 3.7 as regular port fuel injection. Detergents in top tier fuel like Chevron or Shell will help keep the valves clean along with a regular dose of something like Techron.

Fuel pour in additives will do nothing for the intake valves on a DI 5.6. The cleaners I ran were intake system cleaners that you run into the engine through the PCV system or other vacuum source on the intake manifold. I used the T fitting between the throttle bodies that the purge solenoid is hooked to under the intake manifold...

Going to run a can of the Seafoam through mine. Do you run one side of the T fitting at a time or do you run it through the hose coming from the solenoid into the T fitting to catch both sides at once?

armybrat wrote:

DFW2011M56S wrote:The 3.7 as regular port fuel injection. Detergents in top tier fuel like Chevron or Shell will help keep the valves clean along with a regular dose of something like Techron.

Fuel pour in additives will do nothing for the intake valves on a DI 5.6. The cleaners I ran were intake system cleaners that you run into the engine through the PCV system or other vacuum source on the intake manifold. I used the T fitting between the throttle bodies that the purge solenoid is hooked to under the intake manifold...

Going to run a can of the Seafoam through mine. Do you run one side of the T fitting at a time or do you run it through the hose coming from the solenoid into the T fitting to catch both sides at once?

I documented this when I did it...can also go that route:

howto-sea-foam-your-infiniti-m-2011-t604255.html

Good info here. @dfw I purchased a stage 2 snow performance methanol kit, had a little trouble with the sales guy not realizing I needed 2 sprayer nozzles and metal mounts for said nozzles... Never installed the kit. Shipped it back. It was about $650.

DFW,

Please let us know how long your power increase lasts. I'm sure it gradually declines but it would be nice to know whether this would be good to do every year or so. My car just hit 20kmi and it seems to lack power on the low end. I am considering doing this also. It would be good to document the valve condition of a 20kmi engine and perhaps smooth out the acceleration of my car. How long did this take you from start to finish, which cleaning agent did you use, and did you replace all the intake gaskets?

Snake31 wrote:DFW,

Please let us know how long your power increase lasts. I'm sure it gradually declines but it would be nice to know whether this would be good to do every year or so. My car just hit 20kmi and it seems to lack power on the low end. I am considering doing this also. It would be good to document the valve condition of a 20kmi engine and perhaps smooth out the acceleration of my car. How long did this take you from start to finish, which cleaning agent did you use, and did you replace all the intake gaskets?

About 6 hours spread over 2 days. Started late in the evening and finished the next afternoon.

I used fine crushed walnut shells in a media blaster from Harbor Freight and about 5 cans of carb cleaner from Autozone. Some blue paper shop towels and some red shop rags.

Taking the intake off and re-installing it is the clean, easy part. The walnut blasting and carb cleaner are both messy and nasty.

What does the dealer do for their decarb cleaning? I think they charge 350$!

DFW2011M56S wrote:About 6 hours spread over 2 days. Started late in the evening and finished the next afternoon.

I used fine crushed walnut shells in a media blaster from Harbor Freight and about 5 cans of carb cleaner from Autozone. Some blue paper shop towels and some red shop rags.

Taking the intake off and re-installing it is the clean, easy part. The walnut blasting and carb cleaner are both messy and nasty.

Looking further into using the Seafoam, I've read where a few Nissan Techs advise against it for a GDI engine (if you have a bunch of mileage on your car), because there is a possibility of carbon pieces getting between the cylinder walls and the pistons while the engine is running, causing scouring and premature engine wear. From what I've read, doing it the manual way is the best and safest way for your engine. The Seafoam may be a good option if you bought the car new and used it as part of a regular maintenance regimen, as opposed to trying to remove build up from May 2011.

My car has 65k miles on it. I've had it since 52k, and used fully synthetic oil every 5k since I've had it. I have no idea how often the oil was changed or what type oil was used by the previous owner. I heard that fully synthetic oil helps in keeping the build up down to a minimum but I haven't seen any documentation to that effect.

I would like to see what my intake valves look like...if I can get a boroscope or a small fiber optic camera through the spark plug hole maybe I can get a look-see. If they look as bad as the pictures I've seen in this post, I definitely want to have them cleaned.

I did an oil change after getting my m37 will do next one at 3500 to be on the safe side since not sure how often last owner did it. I did put some fuel treatment on the tank and also some sea foam, next oil change ill do sea foam thru the booster line and see how that works

DFW2011M56S wrote: ↑

Fri Dec 30, 2016 2:51 pm

Snake31 wrote:DFW,

Please let us know how long your power increase lasts. I'm sure it gradually declines but it would be nice to know whether this would be good to do every year or so. My car just hit 20kmi and it seems to lack power on the low end. I am considering doing this also. It would be good to document the valve condition of a 20kmi engine and perhaps smooth out the acceleration of my car. How long did this take you from start to finish, which cleaning agent did you use, and did you replace all the intake gaskets?

About 6 hours spread over 2 days. Started late in the evening and finished the next afternoon.

I used fine crushed walnut shells in a media blaster from Harbor Freight and about 5 cans of carb cleaner from Autozone. Some blue paper shop towels and some red shop rags.

Taking the intake off and re-installing it is the clean, easy part. The walnut blasting and carb cleaner are both messy and nasty.

Can you upload the pictures again if you still have them? I’m thinking that the valves in my QX56 probably need to be cleaned. I’m at 110k. I wish that they would have done like Lexus and provided both port and direct injection. It would definitely help with the carbon buildup on the intake valves.