Looking to buy first Silverado and afm is making it hard

[crushNchowda]

guy asks about AFM I see replies about "catch cans" WTF? Did he ask to hear about the direct injection voodoo mumbo jumbo? NO.

 

AFM does suck OP, but can be turned off w/ a device like "range AFM delete" or a custom tune....the issue is that the swap back & forth from 8 to 4 cylinders can be jarring @ times, & it can occur @ the "wrong time" which, in conjunction w/ the fuel saving programming of the TCM (locking/unlocking converter all the time, rolling into "neutral" while coasting & 4 cyl mode then when you put your foot back on @ partial throttle you'll get the common CLANG CLUNK which may emanate from the converter, the yolk/pinion, driveshaft, AFM cylinders or all of it together - as far as I can tell no one really actually knows.

What I do know is that w/ my G8 GT, which had known mechanical & software issues inherent in many of the 6L80E trannies in ADDITION to the AFM junk, was IMMENSELY better even w/ the "2-3 harsh/flare shifting TSB issue" after getting a custom tune & shutting that stuff off.

 

In older models the "hardware" - lifters/valves, springs, maybe rockers & pushrods too were all "weaker" points in the engine design & those parts are directly correlated w/ the function of the AFM system.

 

Also - it really doesn't save much gas mileage in the real world, it is more for excelling @ instrumented testing to eek out the max MPG possible - again going back to Nobama cafe regulations.

 

Other trucks are employing it now too like Dodge, wouldn't be surprise if ford/toyota follow suit.

[mookdoc6]

62K on 2016 AFM in full force!  No oil consumption that warrants any adding of oil even at 10,000 mile oil changes............it probably drops 1/4 of a qt but what engine wouldn't after that mileage?  Anyway can you feel/hear it?  Yup, if you pay attention enough...Do I enjoy 24MPG's on Hwy with AFM  HECK YEAH!  4qty people and all the gear in the back too!

[EDL]

Had Chrysler's AFM equivalent on my 2014 Grand Cherokee and didn't like it when it kicked in because it made the engine and drive train rumble and shudder enough to be annoying.  Just traded it on a 2018 Silverado about 3 weeks ago and after 1100 miles with it on the truck, you can't even tell when it switches in and out of v4 mode at all.  No shuddering, strange noises or anything.  When it's in v4 mode and you need v8 power it switches back over so quick and smooth you never notice it all. 

 

I'm sure AFM helps with mileage and after buying my truck with the 6.2L was wondering what mileage was going to be like.  26.6 MPG on a 2 hour trip from Ohio to Pennsylvania.  22 MPG average on a 19 mile drive to work every day (including hills and traffic lights).  I'm quite happy with it.

 

If DFM is even better, then great.  I'd have no issues buying a truck with it again.  Of course,  my truck is new and this is my opinion of it as of right now.  Other than the annoying shudder and rumble in the Jeep, never had any engine issues due to AFM on the Hemi, so I don't see why I would expect any on the new one.

[Penguin VII]

22 minutes ago, MaverickZ71 said:

As they say, your mileage may vary.  I for one will not ever buy another vehicle with cylinder deactivation of any kind.  I'd buy a 12-year-old vehicle without it before I'd buy a brand new one with it.  I was leery of AFM when I bought my truck, and it has been an oil guzzling, plug-fouling nightmare.  They keep saying that each new generation has all the bugs worked out.  But then you read posts on here saying that folks are still having trouble.  If someone gave me a new truck with AFM, I'd turn off AFM and install a catch can before the thing had 50 miles on it, only use Dexos-rated oil, and check the oil at every fueling stop!  (There is a reason why GM increased the oil capacity from 6 quarts on the 2007-13 models to 8+ quarts on the later models . . . )

Legit curious, what does a catch can have to do with AFM? I'm curious how the two would work in conjunction and why it would be needed.

 

I tuned AFM out of my truck with a Black Bear tune. I don't think it would do much good with the 35s and would hate the drone because of the exhaust. If I was doing 33s and stock exhaust or muffler I probably would have left it.

[mookdoc6]

9 minutes ago, Penguin VII said:

Legit curious, what does a catch can have to do with AFM? I'm curious how the two would work in conjunction and why it would be needed.

 

I tuned AFM out of my truck with a Black Bear tune. I don't think it would do much good with the 35s and would hate the drone because of the exhaust. If I was doing 33s and stock exhaust or muffler I probably would have left it.

Agree....If your into Adding big tires...Exhaust....and all that.....than yeah AFM is not your friend.  But you can get around it if your into all that...........good point!

[Grumpy Bear]

The problem with common sense is it isn't commonly used. God grief Charlie Brown. The vast majority of buyers never have an AFM related issue. It's not unheard of but it is rare.

 

Common sense item #1. Mine works not just perfectly it works imperceptibility and has for nearly 70K miles. Know what that is proof of? That if yours doesn't do the same it has an issue and that issue CAN be solved in the rare case is does happen. If your dealer can't fix it; he's an idiot. Find another.

 

Common sense item #2. People don't joint forums to complain about a truck that works perfectly. Do I need to finish this thought?

 

Common sense item #3. There are about as many driving styles and local conditions as there are trucks and users. Some will never benefit from AFM some will greatly. Blanket statements made on forums based on some knot head that believes his experience is universally true begs the "Here's your sign" moniker. 

 

Common sense item #4. Maintenance. Some do, some don't those that don't wouldn't require statistical  analysis to find that they are in the majority of AFM failures. They get the 'Ya can't fix stupid" title. 

 

Common sense item #5. GM makes money, not trucks nor cars. If AFM was a money looser they would loose AFM. 

 

 

[DEV1ST8R]

I'm not engine mechanic savvy one bit, so just curious if there's more wear-and-tear with or without AFM? I once read somewhere that even though the 4 valves are deactivated, they're still moving, and the lack of combustion could result in more wear...?

 

My experience is that I had it on my 2009 and never even knew until after I traded it in.

Edited July 11, 2018 by DEV1ST8R

[Grumpy Bear]

8 minutes ago, DEV1ST8R said:

I'm not engine mechanic savvy one bit, so just curious if there's more wear-and-tear with or without AFM? I once read somewhere that even though the 4 valves are deactivated, they're still moving, and the lack of combustion could result in more wear...?

 

My experience is that I had it on my 2009 and never even knew until after I traded it in.

Nope. Closed. The cylinder becomes an air spring. 

 

I'm pretty sure the mechanics of 'wear' are grossly misunderstood by the masses. Even some really good mechanics. 

Edited July 11, 2018 by Grumpy Bear

[SierraHD17]

I wouldn't buy a truck with active fuel management because I think the principle of killing the same 4 cylinders constantly is just plain stupid... and it is.  It just leads to ring coking from heat cycling along with the crappy lifter that falls apart.  Then again I would not buy one with a camshaft that slides back and forth in the block with some varying lobe arrangement like the new turbocharged 4 banger in the 2019s.  Making shit overly complicated in attempts to meet government mandates never makes anything better for the end user.  It's a roll of the dice... buy one and get 100000 trouble free miles or more or get a lemon that lives in the shop.  It's always been that way but what changes year to year is the odds.  Are anyone elses new trucks really any better though?  No, they aren't. 

Edited July 11, 2018 by SierraHD17

[Nanotech Environmental]

5 hours ago, greg.lewis.399488 said:

I have a 17 5.3l. Have 41000 miles on it. Put a catch can on about 15000 ago and haven’t had any issues. Can’t even tell it engages most of the time


Sent from my iPhone using Tapatalk

I also have a 17 5.3 with close to the same amount of miles on it. No catch can & probably don't need one. No issues & the AFM is quite seamless.

[twoheeldrive]

A tempest in a teapot.  I have had three trucks now with AFM.  No issues.  I could tell when the 2010 and 2015 switched in and out of 4 cyl mode, but I can't tell when the 2018 goes in/out of  AFM mode at all.  I still lock it out though out of habit. (Pull the shift lever down to M or L and select M5).

 

In fact, I have had no issues with any of my new Chevy trucks.  '09.'10,'15,'18 have all been zero defect vehicles.  Buy new if you can.  The deals are amazing on the 2018's.

 

 

[Donstar]

1 hour ago, SierraHD17 said:

I wouldn't buy a truck with active fuel management because I think the principle of killing the same 4 cylinders constantly is just plain stupid... and it is.  It just leads to ring coking from heat cycling along with the crappy lifter that falls apart.  Then again I would not buy one with a camshaft that slides back and forth in the block with some varying lobe arrangement like the new turbocharged 4 banger in the 2019s.  Making shit overly complicated in attempts to meet government mandates never makes anything better for the end user.  It's a roll of the dice... buy one and get 100000 trouble free miles or more or get a lemon that lives in the shop.  It's always been that way but what changes year to year is the odds.  Are anyone elses new trucks really any better though?  No, they aren't. 

The idea of running cylinders as necessary is brilliant, imo.  There may be some "growing pains" but the idea is sound.  I remember when engines were introduced that burned "unleaded fuel only"  were wrought with criticism.  I'm sure the introduction of EFI (electronic fuel injection) had haters as well.  Reduced fuel consumption is a good thing whether it is mandated or not as it leaves more money in my pocket..  Being easier on the environment is a bonus!

[SierraHD17]

10 minutes ago, Donstar said:

The idea of running cylinders as necessary is brilliant, imo.  There may be some "growing pains" but the idea is sound.  I remember when engines were introduced that burned "unleaded fuel only"  were wrought with criticism.  I'm sure the introduction of EFI (electronic fuel injection) had haters as well.  Reduced fuel consumption is a good thing whether it is mandated or not as it leaves more money in my pocket..  Being easier on the environment is a bonus!

Not really.  Killing the same 4 over and over again does nothing but screw those 4 cylinders up in the long run.  At least with the 19 model year it shifts between all 8 so it passes the problem around... or hopefully alleviates.  The sad part is disabling the afm for most users has no overall I'll effect on the economy.. shows how little it really helps.  That said I will take stuff that runs on all 8 all the time for the next decade or 2.  I would prefer a fuel cell operated electric over this stupidity that will never work properly.  I have nothing against moving forward.

Edited July 11, 2018 by SierraHD17

[aseibel]

11 minutes ago, SierraHD17 said:

The sad part is disabling the afm for most users has no overall I'll effect on the economy.. shows how little it really helps.

I don't know if that statement accurately assesses the value of AFM. Many of the people who disable it do so because they have either tuned, or lifted/leveled with larger tires and/or modified exhaust and probably drive a certain way. Let's hear from some people who disabled AFM on an otherwise stock truck and see if it made any difference for them. AFM is only useful for those who are fuel conscious. The bulk of people on this forum are more concerned with the look & sound of the truck. I would estimate that said group probably doesn't care or want the v4 mode anyway.

[BlackBearPerf]

AFM is typically a fuel saver on the 2014+ models, so we would only suggest disabling it if you have heavy wheels/tires or can't tolerate the sound with your exhaust.