TrueBlue

So, if they can create an app for your cellphone that can show you detailed information about the fuel use in your truck and the remainder thereof, why not just put that functionality in the truck to begin with? I think I know, but regardless of why, they really should.

Well, if the can catches any vapor at all, that it turns into liquid, it should amount to a lesser buildup on the valves. Or so I would think. I just don't know to what extent it might amount to. I installed a catch can on my 2018 Fat Boy, and I did have to empty it from time to time. That small amount would have been sent straight into the throttle body, so I know it was doing at least some good. I would think the same would apply here. Some of us like to hedge our bets. Especially given that we don't get to write our "investment" off like some companies do.

You might want to talk to a mechanic about that. if the PCV inlet to the airbox happens to be upstream of the MAP sensor it might cause an issue. Or possibly if putting the catch can in line between the valve cover and the intake might result in what would amount to a vacuum leak?

Given the fact that there appears to be two separate routes for the vapors to travel back to the intake valves I would tend to agree. If there was only one, and the can was in line, between the pan and the intake I would be much more inclined to equip my truck with one of these. There is no doubt that direct injection does result in carbon build-up on the valves. What is needed is a way to avoid this entirely. As well as that which comes from unburned oil vapors. But until the next technological break-through I guess we're stuck with the issue, or both. The thought of tearing the top end of my engine apart in order to blast the valves with walnuts or some such is not a welcome one.

I've read a few. I just don't think my question has been answered. I find it hard to understand how the catch can can be capturing all of the vapor when it isn't in line with the PCV.

I have the stock 275/60R20 tires on my truck. I've been contemplating a change for awhile now. The other day I followed a late model GMC Sierra into the Home Depot parking lot to ask him what he was running on his truck, which had immediately caught my eye, and that I liked the looks of very much. His tires looked wider than mine, and lower in profile. Turned out he was running 275/55R20 tires on his. I was amazed that they looked so much different than mine. Just 1/2" shorter profile, just over 1" in total height and the same width, but it was very noticeable. Both trucks were equipped with original factory wheels. Different brand than my tires, but I think that the numbers are what tells the story, not the manufacturer/model of the tire itself. Right?

Question on this. If the Separator is between the intake manifold and the left valve cover, but the PCV valve hooks directly from the right valve cover to the air intake tube, isn't that latter process still adding oil vapor from the oil pan/crankcase into the intake valves?

Thank you Sir. In my case I think this is a good thing. Do you happen to know whether or not DCFC is deactivated, along with DFM when in L9?

Thanks for the info @newdude. Does this mean that it is not the typical DFM mode of collapsing lifters that is used to turn all eight cylinders off? Or does it mean that 0-cylinder mode, correctly labeled as Deceleration Mode, is simply DFM affecting all eight cylinders at the same time? Are all lifters collapsed in this mode? edit: I read what you said more slowly. Any time an AFM/DFM engine enters DCFC, all cylinders go back to being active. So the DFM solenoids close the oil flow to re-lock the lifter, and all 8 cylinders become mechanically active again. Engine pumps on all 8 but they cut the fuel off. Closing the oil flow. This puts the lifters in non-DFM mode? Just as they would be if the engine is under load and pulling, but the cylinders do not fire because fuel is cut?

What exactly is happening when this mode activates? Is fuel cutoff, or is it something else?

Yeah, you may be right. Bad cranks, lifters, and valve bodies have certainly come back to bite them. But it's possible that the engineering behind those parts could have made them very difficult to fabricate in such a way that they had dependability and longevity built in. Added to whatever the cause was, is GM's reluctance to own their mistakes and do the right thing. Like replacing all lifters or an entire motor that's been compromised when a lifter grenades and sheds metal into the bowels of the motor, and instead replacing only the specific part(s) that failed and caused the issue. And thereby pushing the correct fix out to beyond the warranty end. And it's not just GM. They're all doing similar things in similar ways. Though in GMs case it's particularly galling since they needed and accepted a taxpayer bailout not so very long ago.

I've not heard that L10 would prevent DFM from kicking in. Does it?

They've done a good job producing them. Now if they could just do a slightly better job at engineering them. Motors and transmissions have been at the heart of vehicles since their early days. Should be able to make them ultra-dependable by now. I've had no major problems with this one, yet. Or with the new body style 2000 Tahoe I bought new back then. But lots of folks have and I just don't understand why it has to be this way.

Haven't seen those posts yet. Must have missed them if they were on this site. Also, didn't know you could disable DFM/AFM with a tune.

Are there any documented cases of this happening to deactivated DFM trucks?