2014+ AFM (Active Fuel Management)

SS502 · December 12, 2018

1 hour ago, Grumpy Bear said:

Few will be interested in this tidbit but take off in M5, when you reach 55 mph (highway only) tap in tow mode. Then select M6. The transmission stays in 5th gear as you are below the upshift point for 6th gear but as M6 is selected the AFM works. This will also work in 4th gear if you haven't reached the 5th gear upshift. I find it useful on rural highways in hilly terrain against light wind. Just stays in 5th 95% of the time and yet allows AFM on the rare flat. Downhill the fuel map shuts of the injectors anyway. When approaching a town tap back to M5 and delete tow mode. My truck is geared 3.23. Exact points will vary with gear and equipment.

Grumpy...is your middle name Google? You Sir are a large pool of some very useful information ?

Grumpy Bear · December 12, 2018

3 hours ago, SS502 said:

Grumpy...is your middle name Google? You Sir are a large pool of some very useful information ?

My head is full of junk I've learned both the easy and the hard way. I'm not afraid to experiment either. Now if I could just remember the right piece at the right time!

3tspapat · December 15, 2018

My eAssist will disable AFM and will not shut off engine at stop using L mode set in any gear all the way up to 7th gear. If set to 8 it will go to V4 but only if 8th is engaged.

Hillwood · December 15, 2018

Why are people so concerned about this topic. I do not understand it. Just drive it. End of story. And yes, even if you can't figure out why the truck has it, it is to save fuel.

DILLY DILLY!!

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EIKON · December 19, 2018

On 12/15/2018 at 10:14 AM, Hillwood said:

DILLY DILLY!!

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Unfortunately while it is designed to save fuel, it adds wear to items.

SS502 · December 19, 2018

30 minutes ago, SMDiesel said:

Unfortunately while it is designed to save fuel, it adds wear to items.

Unfortunately we are stuck with it. Why not at least (special order if need be) offer a DOD delete package? I’d pay extra even though I’m actually getting less in terms of “technology” any day of the week.

EIKON · December 21, 2018

On 12/19/2018 at 4:58 PM, SS502 said:

Unfortunately we are stuck with it. Why not at least (special order if need be) offer a DOD delete package? I’d pay extra even though I’m actually getting less in terms of “technology” any day of the week.

That’s part of GM meeting CAFE at the time of dosing.

You up can always yank the heads and go back to real lifters ;)

Unfortunately at that time you are your own warranty station.

SS502 · December 21, 2018

53 minutes ago, SMDiesel said:

That’s part of GM meeting CAFE at the time of dosing.

You up can always yank the heads and go back to real lifters ;)

Unfortunately at that time you are your own warranty station.

Assuming the rest of the truck makes it past factory warranty...I’ve got the same thoughts ? I will be fully retired by then and will need a hobby ?

EIKON · December 21, 2018

3 hours ago, SS502 said:

Assuming the rest of the truck makes it past factory warranty...I’ve got the same thoughts ? I will be fully retired by then and will need a hobby ?

My 2015 made it 500 hard miles before I put on the kooks longtubes and a full exhaust. Added a clean air separator, modded the air intake, tuned out the AFM, and added an alchohol sensor.

Ran it that way until 50k before I did the cam, converter, and swapped out the AFM lifters for LS7 style.

The AFM lifters looked better than any set of AFMs that I have pulled out of 10-15k engines that had active AFM. Just turning the system off helps a bunch in my opinion. Some guys will argue otherwise.

Ive seen them fail on other trucks even turned off. Not saying otherwise. But I believe turning them off early really helps.

SS502 · December 21, 2018

3 minutes ago, SMDiesel said:

My 2015 made it 500 hard miles before I put on the kooks longtubes and a full exhaust. Added a clean air separator, modded the air intake, tuned out the AFM, and added an alchohol sensor.

Ran it that way until 50k before I did the cam, converter, and swapped out the AFM lifters for LS7 style.

The AFM lifters looked better than any set of AFMs that I have pulled out of 10-15k engines that had active AFM. Just turning the system off helps a bunch in my opinion. Some guys will argue otherwise.

Ive seen them fail on other trucks even turned off. Not saying otherwise. But I believe turning them off early really helps.

No argument here ? Since day one I’ve run mine in L7 to keep the AFM off except when I’m driving on the highway. I have maybe 5% of my total miles driven with the AFM operating and then I’d say it transitions to V4 mode about 20% of the AFM operational miles. Not what I want but it’s helping in my mind anyway ?

3tspapat · December 28, 2018

On 12/20/2018 at 10:09 PM, SS502 said:

No argument here ? Since day one I’ve run mine in L7 to keep the AFM off except when I’m driving on the highway. I have maybe 5% of my total miles driven with the AFM operating and then I’d say it transitions to V4 mode about 20% of the AFM operational miles. Not what I want but it’s helping in my mind anyway ?

Hey this is what I'm also doing as well! For me it also turns off the auto shut off when I stop.

EPIC CAJUN · January 3, 2019

Man screw this AFM bullshit!!! I am currently waiting my truck to be fixed due to two stuck lifters from it. I am on here as we speak to research the best way to turn this "feature" OFF! I do about 90% city driving and on my daily commute, Id bet the AFM is on majority of the time. I bought a V8 for a reason. I shouldn't have to give a little gas, then wait for the computer to make its mind up before I get all 8 cylinders firing as I need more power on my daily drive. I get this has its purpose, but in the city it seems to constantly keep this truck guessing and therefore making for a terrible driving experience.

Sorry for my rant. I have the red ass still this morning and my coffee has not kicked in yet.

Edited January 3, 2019 by EPIC CAJUN

KARNUT · January 3, 2019

Man screw this AFM bullshit!!! I am currently waiting my truck to be fixed due to two stuck lifters from it. I am on here as we speak to research the best way to turn this "feature" OFF! I do about 90% city driving and on my daily commute, Id bet the AFM is on majority of the time. I bought a V8 for a reason. I shouldn't have to give a little gas, then wait for the computer to make its mind up before I get all 8 cylinders firing as I need more power on my daily drive. I get this has its purpose, but in the city it seems to constantly keep this truck guessing and therefore making for a terrible driving experience.

Sorry for my rant. I have the red ass still this morning and my coffee has not kicked in yet.

Easy boy. When engaged your transmission put in in M click you little button up to your last highest gear no V4. When your cruising and you are above 2K on your tack click up to the highest gear. That’s the cheapest way. I did a tune. Some people just leave in the next highest gear but gas mileage would suffer a bit.

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joshuaandrew14 · January 24, 2019

My '16 only has 19k on it and it already sounds like clockwork when I start it up most mornings. Not really sure what I'm hearing, but it doesn't sound like lifters. AFM is a great thought, but that being said, I wish it was something that the operator of the vehicle could control. Just like the auto stop feature on the wife's cruze, I HATE THAT FEATURE, pull up to a parking spot, engine stops - put in park - engine starts right back up just for me to shut it off again.

I feel the AFM switch from V4 to V8 every time it does it. Also, I'd imagine it's because of AFM, but my truck has kind of a rough idle and smells like it runs rich! WTF? I'm just happy she's still under warranty for another 3 years...

KARNUT · January 24, 2019

I hate it, I bought a V8 to get a V8. They added internal equipment and external equipment for cylinder deactivation, more stuff to fail. Some people claim 2 miles more per gallon with it, I didn’t see it. The took one of the most reliable engines out there and increased the odds of failure. I quit buying their cars after they stopped the rear drive sedan, no new GM trucks for me. Long live my 92!

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