First we've heard of anyone trying to clean the intake valves. Did you do it for a reason or just preventative maint as you'd do on all your vehicles ?

 

I did it for preventive maintenance. I had planned on doing it yearly or every 13K to 15K miles.

 

What are we trying to prevent with this cleaning? First I've heard of this on the RL as well. So far so good with the engine as I creep (or barrel) toward 160k on my 2017. The tranny is the weak spot.

 

I think you dodged a bullet and personally, I would quit running things through your mill trying to solve a problem that is less of an issue with modern, computer controlled engines than in decades past....

 

Inlet valve carbon build up is more of an issue now adays with more vehicles having GDI engines vice inlet port injection. If people use a cheap oil or even a synthetic oil that has a high volatility number (i.e., high oil vapor production) then carbon build up could be an issue. Most oil manufactures don't publish their volatility numbers. Inlet valve/combustion cleaners will not remove heavy buildup of carbon but if used pro-actively will help to minimize the build-up. This could prevent the need for soda/walnut blasting of the inlet valves and subsequent high cost.

What I'm really interested in is finding out what process in the engine management system led to all my alarm/warning lights coming in due to spraying cleaner into the engine inlet manifold (at the throttle body).

 

@Georgia TLD , you may want to invest in a simple air-oil-separator if you are concerned. I honestly would be careful on doing these soak & cleans. If anything, remove the intake manifold and clean the back of the valves manually - A simple carb cleaner would also help.

 

I'm guessing the goo caused a sensor misread which cascaded into multiple symptoms that cleared up after a time... I'd check the OBDC codes a couple of times over the next 100 miles and, if fine, quit worrying about it.

 

The PCV systems cleverly designed by the leading manufacturers have caused the stories about carbon buildup to fade in the automobile forums. The manufacturers have built the oil separation function deep in the oil galleries where it can very effectively separate oil and air in an internal engine environment where it is nearly 100% effective. Unlike the external catch cans that were widely touted when Direct Injection was first introduced, modern PCV systems do not use intake manifold vacuum so attempts to connect those catch cans tend to be a hack job trying to introduce a vacuum source that will likely be disadvantageous to the emission systems over time.

 

I have an oil separator installed on the PCV system and dump ~1.5 to 2.0 tablespoons of collected oil every 8K to 10K mile oil change. (I also use higher tier gas to help keep the injectors from carboning up.) I was hoping someone would know which specific sensor(s) gave me all the warning messages so that I may check that sensor(s) for correct/continued operation.

 

I have an oil separator installed on the PCV system

Thanks for adding that you have modified your PCV system.

 

Good luck on your quest. It feels like all the dash lights these days are so integrated with each other that you might as well just have that one old school orange glowing "check engine" light.

 

Since you didn’t capture the DTCs it’s impossible to know what really happened. If the CEL was flashing, then likely the procedure resulted in misfires and the PCM went to limp mode. My guess is the solvent resulted in a rich condition that the PCM could not correct. But it’s just a guess. The AWD warning was caused by the engine DTC.
Like others have said, this engine seems to be immune from intake carbon fouling; I have not heard of a case of carbon build up causing a problem with the J35Y6. I suspect that the risk of injecting solvents directly into the intake is greater than the risk of intake valve carbon deposits eventually causing a problem.

 

Since you didn’t capture the DTCs it’s impossible to know what really happened. If the CEL was flashing, then likely the procedure resulted in misfires and the PCM went to limp mode. My guess is the solvent resulted in a rich condition that the PCM could not correct. But it’s just a guess. The AWD warning was caused by the engine DTC.
Like others have said, this engine seems to be immune from intake carbon fouling; I have not heard of a case of carbon build up causing a problem with the J35Y6. I suspect that the risk of injecting solvents directly into the intake is greater than the risk of intake valve carbon deposits eventually causing a problem.

Exactly. Writing is on the wall on this one. There is no indication (with plenty of time and miles under the the current systems belt) that there is a carbon bulid up issue, so how does it make sense to create a CEL event to solve a non problem?