[alacran]

Glad to hear the engine is running well again. I'm curious what your gas mileage is/will be pre- and post-spark plug replacement.

Which cylinders were the cleanest? The ones farthest from the throttle body?

The deposits may be reduced by using a catch-can instead of dumping the breather oil back into the intake (galley), which we know captures its share of oil.

The deposits aren't helped by the EGR valve-less method of using overlap in the exhaust and intake valve to re-introduce hot exhaust (which then causes the oil vapors to condense on the back of intake valve).

I was looking at that, there is plenty of real estate to mount a catch can but the plumbing would somewhat complicated. The catch can will need two inlets and two outlet to accomodate both valve cover and intake pierce points. Perhaps two inlets and tee the outlets together.

Either way i agree the temperature delta between the oil and the valve seems to promote this build up.

 

[rbarrios]

Techron won't help on the DI engines for controlling intake deposits, since the fuel does not wet the back of the valves. All DI engine designs suffer from this issue, some worse than others. Here's a pic of buildup from the Audi 4.2L V8:

http://forums.quattroworld.com/rs4b7/msgs/58973.phtml

there is a partial truth.
Its true that the intake valves dont get soaked with fuel.
But stuff I had read in the past- hinted at GM's DI's getting a little fuel on the intake valves... (and thus my running Techron every 10K- to help every little bit on my Traverse)
Then recently saw this-- backing up what I had believed or a while....

GM recommends running their GM fuel system treatment PLUS.... (which is Techron Concentrate PLUS)..

Also used during a service procedure...
Im pondering going from every 10K to every oil change....


2011 Cadillac CTS | CTS VIN D Service Manual | Document ID: 2863222
#PIP5029: Engine Misfires Due To Major Carbon Deposits On The Intake And/Or Exhaust Valves - (May 29, 2012)
Subject: Engine Misfires Due To Major Carbon Deposits On The Intake And/Or Exhaust Valves

Models: 2008 - 2012 Cadillac CTS, STS
2008 - 2010 Chevrolet Cobalt SS, HHR SS
2007 - 2010 Pontiac Solstice GXP
2007 - 2010 Saturn Sky Redline
2009 - 2012 Buick Enclave
2009 - 2012 Buick Lacrosse
2009 - 2012 Chevrolet Traverse
2009 - 2012 GMC Acadia
2009 Saturn Outlook
2010 - 2012 Cadillac SRX
2010 - 2012 Chevrolet Camaro, Equinox
2010 - 2012 GMC Terrain
With any of the Following Direct Injected Gasoline Engines:
2.0 (RPO LNF)
2.4L (RPO LAF, LEA, or LUK)
2.8L (RPO LAU)
3.0L (RPO LF1)
3.6L (RPO LFX or LLT)

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

Some customers may complain of a MIL and engine misfire. In some cases, the misfire may be more apparent on a cold start, may count on a single cylinder or several cylinders, and may or may not be felt by the driver. Upon inspection, the technician will find one or more misfire codes (DTC P0300-P0306) stored in the ECM and SI diagnosis may or may not isolate the cause of the misfire depending on whether the intake/exhaust valves are sticking at the time of the diagnosis.

This may be the result of major carbon build up on the intake and/or exhaust valves as shown below so the misfires should not have appeared until the engine has accumulated around 5,000 miles or more.





.







Recommendation/Instructions:

If this concern is encountered, perform SI diagnosis. If SI diagnosis isolates a valve sealing concern and/or eliminates everything else external to the engine, decarbon the engine with Upper Engine and Fuel Injector Cleaner by following the guidelines below:

Important Extreme care must be taken not to hydrolock the engine when inducing the cleaner, especially if it is induced without Kent Moore Tool # J-35800-A. If too much cleaner is induced at too low of a RPM, or if you force the engine to stall by inducing too much cleaner at once, the engine may hydrolock and bend a connecting rod(s).
1. In a well-ventilated area with the engine at operating temperature, slowly/carefully induce a bottle of GM Upper Engine and Fuel Injection Cleaner into the engine with RPM off of idle enough to prevent it from stalling (typically around 2,000 RPM or so). Depending on the engine configuration, induce the cleaner through the throttle body or an engine vacuum hose/pipe. For best results, it is suggested to induce the cleaner with Kent Moore Tool # J-35800-A (shown below).
2. Turn the engine off after inducing the cleaner and allow the cleaner to soak with the engine off for 2.5 to 3 hours (Do not let cleaner soak for more than 3 hours as remaining deposits may start to harden back up again).
3. Add a bottle of GM Fuel System Treatment Plus to the fuel tank and fill the vehicle with one of the Top Tier gasolines listed at http://www.toptiergas.com and/or in the latest version of 04-06-04-047 (USA) or 05-06-04-022 (Canada). See Bulletin 05-00-89-078 for more details on GM Fuel System Treatment Plus.
4. Test drive the vehicle extensively to circulate the GM Fuel System Treatment Plus, which will help to eliminate/reduce any remaining intake valve deposits.
5. Re-evaluate the concern to determine if it is repaired or improved at all. If the concern is improved but not repaired, it may be necessary to perform the above decarboning process a 2nd time.



6. To complete the repairs, advise the customer to only use one of the Top Tier Gasolines listed at http://www.toptiergas.com and/or in the latest version of 04-06-04-047 (USA) or 05-06-04-022 (Canada) to minimize future deposits. It can also be recommended to add a bottle of GM Fuel System Treatment Plus at every oil change as mentioned in the latest version of 04-06-04-051.
Kent Moore Tool # J-35800-A
Upper Engine and Fuel Injector Cleaner

 

[alacran]

pictures up

#4 spark plug

http://i144.photobucket.com/albums/r171/alacran2000/Traverse%20LLT%20engine/IMG_1314.jpg

#4 intake valves

cleanest intake valves

dirtiest intake valves or one of the two dirtiest pair llt

http://i144.photobucket.com/albums/r171/alacran2000/Traverse%20LLT%20engine/IMG_1328.jpg


Deposits out of one cylinder, there is more but no pictures taken.

Bonus shots
intake without the foam cover (no glue)

http://i144.photobucket.com/albums/r171/alacran2000/Traverse%20LLT%20engine/IMG_1345.jpg

fuel system shot (Vee foam removed)

before installing the intake

one interesting observation, i wonder if you noticed it too. The ground strap has a semicircle or arch cut into it from use. it is an indentation on the electrode side from front to back. I will try to get a better shot of it.

 

[XRDreamliner]

I may have missed it, but how many miles on your Traverse alacran?

Nice pictures... looks like GM isn't any better job at controlling intake valve deposits than any other automaker with DI engines.

 

[alacran]

I bought the LTZ with 70K in May 2012. The first thing i did was check the air filter, the so called long life air filter, and it was plugged (meaning no light was passing through it). Then, i realized i spilled milk shake goop onto the engine. I wonder who much the plugged air filter contributed to this mess.

Truck has a K&N air filter, PF63 oil filter, and NGK Laser iridium.


Thinking of a catback modification but next on the list is rear KYB shocks. The delco shocks are too easy to compress.

 

[rbarrios]

what brand gas you run the majority of the time?

TO help that out-
I definitely would run several bottles of Techron.

Excellent Pictures too.

 

[XRDreamliner]

Truck has a K&N air filter, PF63 oil filter, and NGK Laser iridium.

I saw in the other thread that you replaced the ignition coils. Is that still the case?

 

[alacran]

yes but i stayed with Bosch, D501C, and that was done as preventive maintenance or to avoid having to pull the intake to replace a coil. Knowing what i know now or in hindsight that was probably overkill as i have no issues pulling the intake for that and do some cleaning.

 

[greentraverse]

The first thing i did was check the air filter, the so called long life air filter, and it was plugged (meaning no light was passing through it).

There's a discussion, I believe on the K&N site, about air filters and that todays filters filter BETTER as they load up. They had some info regarding the pressure drop across the filter and the size of the particles getting through the filter. So simply changing it because you can't see light through it MAY not be the appropriate thing to do.

 

[alacran]

There's a discussion, I believe on the K&N site, about air filters and that todays filters filter BETTER as they load up. They had some info regarding the pressure drop across the filter and the size of the particles getting through the filter. So simply changing it because you can't see light through it MAY not be the appropriate thing to do.

Find me that source. The plugged filters would increase the vacuum pressure in the PCV system.

Also, just for you i will check a new filter next time i am at the store.

 

[rbarrios]

Ive been hearing this too-..
Most recently on GOSS's garage on that Motorweek show...

They said that the Mass air flow sensor will calibrate the fuel for the amount of air getting to the engine...


so thats why they went to almost 50,000 miles on air filters.

 

[greentraverse]

Find me that source. The plugged filters would increase the vacuum pressure in the PCV system

Put www in front of this: knfilters.com/filter_facts.htm#FACTS

It's down near the bottom of the article. Here's the important quote: "So as dirt accumulates, the performance advantages of a K&N air filter can increase!"

 

[alacran]

no arguement on the MAF and its ability to adjust accordingly. However, a plugged filter needs to be serviced in order to run the engine in optimum condition.

My point is - if the filter is dirty or loaded with debris the engine will pull air from somewhere and and the PCV is right there. The only problem with pulling air from the PCV is the intake valve getting coated with oil. The catch cans being installed on these motors allow the removal of the oil from the PCV air stream.

I have no problem cleaning my air filter to avoid starving the engine of fresh air but more importantly to keep the oil out of the intake. Either way it is time for a catch can. need to research the PCV system on the Camaros first.

 

[rbarrios]

very good point alacran.

This also means that air will take the path of least resistance....
Meaning that if the air filter cover was not put on securely- or theres a break in the tubing---- unfiltered air will make its way in...
Usually you wont notice-- but this cleary shows up on Used oil analysis- as high silicon.

I know I had one once- with silicon a little higher than normal..
The suggestion was to check the filtration system.
I went to check- and happen to put my hand on the air cover-- and lean over to inspect--- 'POP'
the weight I put on the cover made it pop into place.... there was the leak...

 

[alacran]

Looks like we have two PCV lines. One from Holden (Front valve cover) and one from the Camaro and CTS (Rear valve cover). Basically, in my research i found catch cans being installed on both applications and in the catch cans are installed two unique ways for each.

Holden


camaro
[img]http://www.camaro5.com/forums/attachment.php?attachmentid=167987&stc=1&d=1285635049

Any ideas as to why have two PCV lines? Also, upon further inspection the camaro also has two PCV lines. I think it is time for a separate thread on this issue.

 

[bayner66]

From the photos, the catch can seems in series with the lines unless I'm missing something. You have the outlet and line from the engine interior feeding into the catch can and the line from the can to the intake which provides the vacuum to suck out the vapors and equalize the crank pressures caused by the rotating parts. The can which is somewhat cooler than the engine's interior then causes most of the oil vapor to condense to the bottom of the can. Without the can, the same thing happens with some of the vapors going into the engine and some condensing out onto the trough in the air intake line like it was designed to do.

 

[DVelasco68]

You could probably use one catch can, and use metal 'T's to route the hoses to the one catch can...

Or you could run one catch can on each side...

I was looking at that, there is plenty of real estate to mount a catch can but the plumbing would somewhat complicated. The catch can will need two inlets and two outlet to accomodate both valve cover and intake pierce points. Perhaps two inlets and tee the outlets together.

Either way i agree the temperature delta between the oil and the valve seems to promote this build up.

 

[alacran]

very interesting...

Did you ever run techron before this?

Im curious to see the buildup

No Techron for me. I dont believe in that stuff.

 

[rbarrios]

techron is called for- in the GM service bulletin when carbon is removed 'by hand'... it helps remove the stuff they couldnt get to.

 

[XRDreamliner]

techron is called for- in the GM service bulletin when carbon is removed 'by hand'... it helps remove the stuff they couldnt get to.

Explain how the Techron helps to get on the back of the intake valves on a Direct Injection engine? It can't. Believing otherwise is drinking the GM Kool-aid.

Physical cleaning and soaking is the only way to remove these deposits.