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2014+ AFM (Active Fuel Management)

Ron.s

By Ron.s
in Engines & Drivetrain

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Stex Senior Enthusiast

Stex

Posted
Posted

It is the lifters that worry me. The system allows the lifters to collapse. Just saw a 2010 sub get a new rebuilt 5.3 because of lifters. 120,000 miles.

 

It was more cost effective to replace the engine than to tear the old one down for lifters. 23 hour job for lifters. Paid a little more but got a rebuilt engine. They suspect the afm causing the lifters to fail. IF I buy another GM the afm will be off from the first day. Or trade often.

 

And yes I have heard they have improved the lifters. However you will not know for sure till miles are on the truck and most likely out of warranty.

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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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WendysOrBust Enthusiast

WendysOrBust

Posted
Posted

It is the lifters that worry me. The system allows the lifters to collapse. Just saw a 2010 sub get a new rebuilt 5.3 because of lifters. 120,000 miles.

 

It was more cost effective to replace the engine than to tear the old one down for lifters. 23 hour job for lifters. Paid a little more but got a rebuilt engine. They suspect the afm causing the lifters to fail. IF I buy another GM the afm will be off from the first day. Or trade often.

 

And yes I have heard they have improved the lifters. However you will not know for sure till miles are on the truck and most likely out of warranty.

Interesting, I have seen issues with the AFM lifters but its not a complete engine rebuild. Just simply replacing the lifters. A member on here with a slammed 6.2 posted about it a while ago. He had low miles too.

Stex Senior Enthusiast

Stex

Posted
Posted

Interesting, I have seen issues with the AFM lifters but its not a complete engine rebuild. Just simply replacing the lifters. A member on here with a slammed 6.2 posted about it a while ago. He had low miles too.

The 5.3 lifter replacement is 23 hour of work according to the book. So in the case I cited, they went with a rebuilt engine swap. AFM Lifters are a know problem for the 900 series trucks. GM says the redesigned lifters are now good to go but I would still kill the AFM on a new truck.

Ryans14ThungstunZ71 Enthusiast

Ryans14ThungstunZ71

Posted
Posted (edited)

Doesn't seem to bother me much, but I wonder if anyone's tried this Range product:

 

http://www.rangetechnology.com/products/range-v8

The lifters and pushrods on the 2010s are weak from what ive read on forums. I had my 2010 z71 5.3 started having issues at 36000 miles with random noises under the hood. Took it to the dealership 4 times for the noise and loss of power but they said they didn't hear it and wouldn't look into unless there was total engine failure. Looked online for answers and some guys had the same issues and it cost them tons to get it fixed. During my reading into the issue I was having someone on a forum said 2010 Chevys were made cheaper because of the bail out not 100% if that's true but I didn't want to wait for total engine failure so traded it to the same dealership that wouldn't look into the problem for a 2014 Silverado. Sales manager called me a few days after with a long list of repairs they had to do to the truck after the techs took a good look at it. 3-4k in repairs along with a new set of tires. I think I made a wise choice.

It is the lifters that worry me. The system allows the lifters to collapse. Just saw a 2010 sub get a new rebuilt 5.3 because of lifters. 120,000 miles.

 

It was more cost effective to replace the engine than to tear the old one down for lifters. 23 hour job for lifters. Paid a little more but got a rebuilt engine. They suspect the afm causing the lifters to fail. IF I buy another GM the afm will be off from the first day. Or trade often.

 

And yes I have heard they have improved the lifters. However you will not know for sure till miles are on the truck and most likely out of warranty.

Edited by Ryans14ThungstunZ71
  • 2 months later...
  • 1 month later...
GsBowtie Enthusiast

GsBowtie

Posted
Posted

Hey Guys,

 

See this thread about my brothers 2014:

 

http://www.gm-trucks.com/forums/topic/174526-my-brothers-2014-silverado-crew-53-collapsed-lifter-afm-issues/

 

I didn't relalize this thread existed until today. I'm not sure if it's related or not, but worth noting, especially in light of the fact that he thought his stopped hammering when it switched to V4 mode.

 

I have run my truck in m5 and I do like the way it shifts, and performs in M5 which turns the AFM off. Just my preference. I also do not believe the fuel mileage suffered much at all, and may actually have improved in M5 (I have a lot of back roads, no highway to and from work)

 

My brother did confirm that at 28k, his truck is not using an oil, so that's a good thing. Hopefully that was resolved from the prior generation trucks.

 

-G

jasch1124 Enthusiast

jasch1124

Posted
Posted (edited)

Just wanted to chime in on my expereince and opinion on the AFM.

 

Mine will regularly shift into V4 mode on the highway when I have it in cruise in the 55-65 range. Above 65 it likes to stick more to the V8 mode. Shifting between 4 and 8 is seamless but not completely undetectable. It could also be the truck shifting to accomodate the drop/increase in power but a passenger wouldn't know the difference. The instant gas mileage display can jump up past 20 easily when it dives in V4 mode and have had strictly V8 trucks in the past and from what I can tell the display seems accurate.

 

I've read of products users have recommended on this forum that you could plug in to force it to stay in V8 mode. Keeping in V8 serves no purpose for me. I'd actually like to see a product that could keep it in V4 longer. A family member has a 2011 GMC Terrain with an ECO button. It's already a V4 so I assume it plays with the RPMs/Transmission in her vehicle. It definitely feels sluggish when pressed but for me, I'd accept the sliggish performance for highter fuel economy as long as I have the option to disable it when I want the performance restored.

 

Other vehicles out today have the ability to switch between driving modes. Ideally I'd like to see a Sport mode which would keep it in V8, Normal mode which would be the stock setup we have now and an Eco mode which would push it to use V4 mode more often than V8.

 

AFM system has been great to me so far, but the addition of something along the lines of a 'Mode Selector' would really take it above and beyond.

Edited by jasch1124
  • 3 weeks later...
robvas Enthusiast

robvas

Posted
Posted

Just wanted to chime in on my expereince and opinion on the AFM.

 

Mine will regularly shift into V4 mode on the highway when I have it in cruise in the 55-65 range. Above 65 it likes to stick more to the V8 mode. Shifting between 4 and 8 is seamless but not completely undetectable. It could also be the truck shifting to accomodate the drop/increase in power but a passenger wouldn't know the difference. The instant gas mileage display can jump up past 20 easily when it dives in V4 mode and have had strictly V8 trucks in the past and from what I can tell the display seems accurate.

 

I've read of products users have recommended on this forum that you could plug in to force it to stay in V8 mode. Keeping in V8 serves no purpose for me. I'd actually like to see a product that could keep it in V4 longer. A family member has a 2011 GMC Terrain with an ECO button. It's already a V4 so I assume it plays with the RPMs/Transmission in her vehicle. It definitely feels sluggish when pressed but for me, I'd accept the sliggish performance for highter fuel economy as long as I have the option to disable it when I want the performance restored.

 

Other vehicles out today have the ability to switch between driving modes. Ideally I'd like to see a Sport mode which would keep it in V8, Normal mode which would be the stock setup we have now and an Eco mode which would push it to use V4 mode more often than V8.

 

AFM system has been great to me so far, but the addition of something along the lines of a 'Mode Selector' would really take it above and beyond.

I would swear one of the tuners had a 'eco' tune that would turn the AFM on more often?

  • 2 months later...
Eddie 70 Senior Enthusiast

Eddie 70

Posted
Posted

It's been a while since I had my 07 GMC with AFM but I remember it being very easy for the truck to shift out of AFM mode. I just picked up this 14 on Saturday and it seems to me that the truck stays in AFM mode longer. I can even gain speed on the interstate while in AFM mode. I have to ease down on the gas but I can gain speed. It seems to me it has been upgraded since the 07.

11bDad Enthusiast

11bDad

Posted
Posted

The AFM in my 2015 Silverado 4.3L (new) would be constantly engaging & disengaging to the point it drove me crazy. At a constant speed it would do this every 10 seconds with a shudder in the steering wheel and gas pedal. AFM disabler arrived Friday & it's like a different truck.

  • 4 weeks later...
uptou2bu Enthusiast

uptou2bu

Posted
Posted (edited)

Seamonster I was wondering the same thing about the gear ratios. I would think it would matter considering from what I have read everything seems to affect it; fuel pressure, torque, transmission shift, torque converter, oil pressure, manifold vacuum, brake vacuum, voltage, temperature, etc. With my limited knowledge I believe these systems are way to sensitive when comes to engaging and disengaging. For example there is no reason these vehicles should drop out of V4 mode when going up a slight incline like an overpass on the interstate and they should be able to engage V4 and stay that way with the cruse control set at 75mph on at flat interstate highway. I was told this morning by a new purchaser that the 2015 Silverado manual actually states that it supposed to do that. I have a 2014 Silverado LTZ 4x4 which I purchased 11-20-15 and the V4 mode will not engage above 58 mph on flat interstate highway and I just tried this on a 600 mile run; all interstate. Average MPG was 16.3 which is deplorable and a far cry from what it should be getting. (58 MPH ON THE INTERSTATE WILL GET YOU KILLED) 11-21-15 advised dealer of issue while in route, they said drive it let it adjust and bring it back when you get back in town. Two days later spoke to the dealer advised them of no change and poor performance and they said all of them are that way. That didn't settle well with me and I advised them I stopped payment on the 14K down payment check. That got their attention, I said you can fix it or keep it. With all this being said I believe that the GM AFM system is inadequate at best and they are completely misleading customers of the capability reliability of this system.

Edited by uptou2bu
  • 2 months later...
shockedimpy Enthusiast

shockedimpy

Posted
Posted

Used the Diablo Trinity to disable the AFM. No longer do I need to endure the constant changes in cylinders. Gas efficiency went slightly up and I will never ever use AFM ever again. Ever. Now to install the 87 tune, and see how the tranny shifts

  • Like 1
cmysstailights Enthusiast

cmysstailights

Posted
Posted

For my camaro i installed a vitesse throttle controller, it changes the pedal sensitivity. Its a 2010 2ss 6spd tune headers intake i can see 28mpg on highway with eco mode selected. Too bad noone makes that for the truck

 

Sent from my SM-G900P using Tapatalk

  • 3 weeks later...
Badass69 Senior Enthusiast

Badass69

Posted
Posted

There is a lot more detriment to the 4 cylinder mode than crappy lifters....... oil consumption from ring coking becomes a reality in the cylinders that deactivate. I have torn lots of the LS ones down and that's what happens with the constant cycling..... I deactivated mine via tuning today on my 2015 and if it ever gives me a bit of trouble it's all the reason to do a cam swap and delete it mechanically.

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