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2014+ AFM (Active Fuel Management)

Ron.s

By Ron.s
in Engines & Drivetrain

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SteveC Enthusiast

SteveC

Posted
Posted (edited)

It seems like an 8 cylinder engine should run al 8 all the time. Fuel savings are great but if I wanted a V4 that’s what I’d buy. Even with my 5.3 (I don’t need a lot of power) I think I want all 8 all the time. I get trying to be efficient but something seems odd about taking half the engine out of the equation many times in the course of a 2 mile drive to work.

 

The power drain is a little concern (I don’t want to keep plugging it in and out) but it seems like a simple (and reversible) way to gain some performance. And let’s be honest, while good economy is nice, or we were that concerned about gas mileage we’d be driving a Civic.

Edited by SteveC
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oldmann
oldmann

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.

pm26
pm26

No, it does not. Not even close. The only Cadillacs that possibly exceeded the weight of 2014 GM crew cab 1500 4x4 pickups were the old land yachts (1976 and older) models. I believe that a 1976 Ca

seamonster
seamonster

Whats up with the name calling?   Cant you see we agree----the AFM feels like a gear shift!   Many people want 6 and 8 speed tranny and then complain they can feel AFM. That is what I dont unders

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diyer2 Senior Enthusiast

diyer2

Posted
Posted

If I had a 2 mile drive to work I would put the trans. in manual 4,5, 6, 7th gear depending on the roads driven, no AFM activated.

2 miles it's not getting up to temperature. The oil, trans fluid, differentials don't dissipate moisture. 

The exhaust doesn't get warm enough to rid its self of moisture either promoting rust.

I would take the long way to work sometimes to get the temps up. YMMV.

The old lady car that was driven to the library. 

:)

   

 

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rkj__ Enthusiast

rkj__

Posted
Posted
If I had a 2 mile drive to work I would put the trans. in manual 4,5, 6, 7th gear depending on the roads driven, no AFM activated.
2 miles it's not getting up to temperature. The oil, trans fluid, differentials don't dissipate moisture. 
The exhaust doesn't get warm enough to rid its self of moisture either promoting rust.
I would take the long way to work sometimes to get the temps up. YMMV.
The old lady car that was driven to the library. 
[emoji4]
   
 


I have a short in town commute. I usually put my 6 speed in L5 for it.

The AFM does not bother me on the highway much, but I’m not a big fan of it for city driving.


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SteveC Enthusiast

SteveC

Posted
Posted

Hmm. I guess I didn’t realize people drove around in “L” all the time. I just assumed that was for special circumstances and towing and such. 

F4Gary Enthusiast

F4Gary

Posted
Posted (edited)

I put mine in M6 all the time.  Eliminates the V4.  There is no "L".

Edited by F4Gary
rkj__ Enthusiast

rkj__

Posted
Posted
2 hours ago, Shakeydeal said:

IIRC, M6 will activate V4 when it shifts into 6th gear. M5 will not.

 

Shakey

I'm pretty sure when in L6, my 2018 6 speed still goes into V4 in any gear it wants.  It definitely never goes into V4 when in L5.

SDfromSD Enthusiast

SDfromSD

Posted
Posted
2 hours ago, rkj__ said:

I'm pretty sure when in L6, my 2018 6 speed still goes into V4 in any gear it wants.  It definitely never goes into V4 when in L5.

Correct. Needs to be below the “top” gear.

Depending on what vehicle/model user F4Gary has, if he has the 8-sp tranny for him 6 or 7 would work.

It also goes in to V4 mode with tow-haul on unfortunately. I wish there was a DIC selection to turn it off rather than spending money on a device.

rkj__ Enthusiast

rkj__

Posted
Posted
Just now, SDfromSD said:

 I wish there was a DIC selection to turn it off rather than spending money on a device.

Yes, that would be nice, if the driver could choose. 

 

V4 mode does not bother me at all on the highway, when I'm using cruise control.  I like to save fuel on long trips.  I don't desire to delete AFM entirely, it would just be nice to choose when it can activate. 

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Ozer Enthusiast

Ozer

Posted
Posted

On my 2014 i noticed the transmission gets confused a lot more when AFM is active. It clicks and clunks more so than when its in V8 mode only.

I used a hand held tuner to tune and disable AFM. Im only getting 2-3 mpg hit by doing that but truck drives better so its worth it.

F4Gary Enthusiast

F4Gary

Posted
Posted
On 11/15/2018 at 10:19 AM, SDfromSD said:

Correct. Needs to be below the “top” gear.

Depending on what vehicle/model user F4Gary has, if he has the 8-sp tranny for him 6 or 7 would work.

It also goes in to V4 mode with tow-haul on unfortunately. I wish there was a DIC selection to turn it off rather than spending money on a device.

You guys are correct.  Just noticed that the other day.  M6 allows V4.  M5 does not.  Sorry for the misinformation.

 

  • 2 weeks later...
Doublebase Enthusiast

Doublebase

Posted
Posted
On 11/15/2018 at 11:29 AM, rkj__ said:

Yes, that would be nice, if the driver could choose. 

 

V4 mode does not bother me at all on the highway, when I'm using cruise control.  I like to save fuel on long trips.  I don't desire to delete AFM entirely, it would just be nice to choose when it can activate. 

I feel the same way, the V4 is great for me in a lot of instances and gets me great gas mileage, but there are times I'm noticing where I wish I could shut it off. Like if I'm stuck behind someone driving slow...the thing bogs down and constantly switches in and out of V4, seemingly not knowing what to do. But those are rare occasions and the person really has to be driving slow, otherwise I love the V4. If I towed or plowed, I'd definitely want the V8 on all the time.

  • 2 weeks later...
bhales Enthusiast

bhales

Posted
Posted

do i still need to even bother with the AFM delete on a 2018 Motor or should i just not worry about it. I turned it off on my old 2008 6.2L for a bout a year but never really saw a difference. im pretty sure the AFM is what is killing my FIL's 2007 5.3 motor

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
On ‎11‎/‎15‎/‎2018 at 10:19 AM, SDfromSD said:

Correct. Needs to be below the “top” gear.

Depending on what vehicle/model user F4Gary has, if he has the 8-sp tranny for him 6 or 7 would work.

It also goes in to V4 mode with tow-haul on unfortunately. I wish there was a DIC selection to turn it off rather than spending money on a device.

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.  

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