2012 Yukon 6.2 Denali with AFM

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bobsr

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Hello,

Is the AFM the old 8-6-4 which reduced the number of cylinders the engine has running at any given time?

Is that what a 2012 6.2 Denali with a AFM would have? Was this engine available in 2012 with or without this AFM? Loklng at a used one with about 100,000 miles which has AFM. Seems it might be an issue.

Thanks.
 

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pretty sure all the 2012 have AFM, you would need to either turn it off with a tune, or do a hardware delete and have the ecm re programmed to completely remove it and by doing that I believe you loose the flex fuel capability but I could be wrong. @swathdiver probably has more info
 

the_tool_man

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bobsr:

I just bought exactly the same thing; a 2012 Yukon Denali 6.2 with AFM and 99k miles. The system came on all of these vehicles from the factory.

First of all, while the concept is the same as the old 8-6-4 system from the early 1980's, the actual implementation is vastly better. Modern electronics and variable valvetrain geometry have supplanted the jury-rigged, primitive systems of old. When it works, it works very well, and isn't especially noticeable unless you have an aftermarket exhaust system, which audibly reveals V4 mode. GM decided to develop the system and install it on many vehicles to help them meet government CAFE requirements. Anecdotally, the savings is around 5% on average. Actual fuel savings varies with terrain and driving style.

Secondly, by 2012, it is my understanding that the system had become pretty reliable, provided proper oil change intervals were followed. The system relies on solenoid valves to divert oil pressure to retractable pins on the valve lifters, allowing them to collapse. Dirty oil reduces the likelihood that this system will work properly.

Thirdly, having said that, with unknown service history and the accumulation of miles, it stands to reason that AFM is nevertheless a potential failure point. For that reason, I chose to deactivate AFM on my Yukon shortly after I bought it. I did this using a custom tune. There is a plug-in device, called a Range module, that effectively does the same thing. After studying the operation of the AFM system, I determined that if it is never actuated, there is no risk of failure; at least none that I can determine. For me, the mileage benefit of AFM was negligible. And I wanted the peace of mind of knowing the valvetrain would last.

I would not, and did not let the existence of AFM deter me from buying what is otherwise an excellent vehicle with a fantastic engine.
 
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bobsr

bobsr

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pretty sure all the 2012 have AFM, you would need to either turn it off with a tune, or do a hardware delete and have the ecm re programmed to completely remove it and by doing that I believe you loose the flex fuel capability but I could be wrong. @swathdiver probably has more info

Thanks for your comments. I have a 2003 Yukon with the 5.3 with now 325,000 + miles, and have been running Mobil 1 5W-30 since new. Ordered this and it took me 5 months to get it in 2002, and I hate losing the "barn doors" with no third seat. Minimal problems until now, with increased oil usage and small things failing that make my wife nervous. TIme to get something newer, and the 2012 with around 100,000 looks promising.

I have the dark bue SLT with auto ride and most options, including the then new "flex fuel" option. MAYBE used it once when in Pennsylvania and I bought some of that fuel. But I did have to replace some kind of a valve for that system and that cost me $700-- at the dealer. So the "flex fuel" option was a bad choice. But now I guess they all come with it. We still don't have that fuel generally available in New England.
 
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swathdiver

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Thanks for your comments. I have a 2003 Yukon with the 5.3 with now 325,000 + miles, and have been running Mobil 1 5W-30 since new. Ordered this and it took me 5 months to get it in 2002, and I hate losing the "barn doors" with no third seat. Minimal problems until now, with increased oil usage and small things failing that make my wife nervous. TIme to get something newer, and the 2012 with around 100,000 looks promising.

I have the dark bue SLT with auto ride and most options, including the then new "flex fuel" option. MAYBE used it once when in Pennsylvania and I bought some of that fuel. But I did have to replace some kind of a valve for that system and that cost me $700-- at the dealer. So the "flex fuel" option was a bad choice. But now I guess they all come with it. We still don't have that fuel generally available in New England.

Howdy Bob. John laid out the features and how most of folks deal with AFM succinctly. I will only add that the Flex Fuel capability is not lost when de-activating AFM and that this generation does not use that special and expensive FlexFuel sensor. These engines run great on E85.

Is the Denali you're looking at 2WD or AWD?
 
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bobsr

bobsr

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Howdy Bob. John laid out the features and how most of folks deal with AFM succinctly. I will only add that the Flex Fuel capability is not lost when de-activating AFM and that this generation does not use that special and expensive FlexFuel sensor. These engines run great on E85.

Is the Denali you're looking at 2WD or AWD?

Hello,

Thanks for your comments. The Denali I am looking at has AWD and most options. 100,000 miles and records seem to be clean.
I live where we get snow and ice and salt etc on the roads in the winter. I try to wash vehicles regularly in the WInter. The 2003 I think has the 4wd system which has been excellent with no issues.


I doubt if the 100,000 miles extensive service was done, but maybe this has a different service schedule than a 2003. Dealer charged me about $ 1,000 to do it, with a tune up, all fluids changed etc etc. back then.

I would suspect a service contract might be in order for this vehicle.

Any comments on those? I know there are a bunch of scams out there, but I think the new and used car dealers also offer these, including the seller of the vehicle I am looking at. But I don't have the details yet. Have to drive a couple of hours today to actually look at the vehicle for sale from a used car dealer.
 

swathdiver

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Hello,

Thanks for your comments. The Denali I am looking at has AWD and most options. 100,000 miles and records seem to be clean.
I live where we get snow and ice and salt etc on the roads in the winter. I try to wash vehicles regularly in the WInter. The 2003 I think has the 4wd system which has been excellent with no issues.


I doubt if the 100,000 miles extensive service was done, but maybe this has a different service schedule than a 2003. Dealer charged me about $ 1,000 to do it, with a tune up, all fluids changed etc etc. back then.

I would suspect a service contract might be in order for this vehicle.

Any comments on those? I know there are a bunch of scams out there, but I think the new and used car dealers also offer these, including the seller of the vehicle I am looking at. But I don't have the details yet. Have to drive a couple of hours today to actually look at the vehicle for sale from a used car dealer.


No experience with them but Wes might know. Check everything, every knob and switch and feature including the cruise control and heated steering wheel, cooling seats, side blind zone, back up camera, moonroof, power seats front to rear, etc.

When you drive it, set the driver's information center to the instant mpg so you can see when she goes into V4 mode and feel for that. Should be seemless or nearly so.

Good luck!
 
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bobsr

bobsr

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No experience with them but Wes might know. Check everything, every knob and switch and feature including the cruise control and heated steering wheel, cooling seats, side blind zone, back up camera, moonroof, power seats front to rear, etc.

When you drive it, set the driver's information center to the instant mpg so you can see when she goes into V4 mode and feel for that. Should be seemless or nearly so.

Good luck!

Great advice! Thanks. Haven't bought a used vehicle for probably 40 years. But 60 + grand for a new Yukon seems over the top. Have to spend a lot of time reading the instructions for all that new (to me) stuff like rear camera, side blind zone, cell phone integration, and the whole driver information center. I had the OEM suplied XM radio back then, and on star (never used it or paid for it), and a pretty basic (by todays standards) driver information center. But at the time, it was a big deal. My average for 325,000 miles: 16 mpg .

No GPS at that time, except my Magallan GPS system stuck on to the windshield, with the antenna through the moon roof. Cost me over $1,000 at that time from Costco. But was magic for a guy on the road a lot for business. But I had learned how to use it because it was the same system Hertz first used. All this technlogy is only as good as your ability to learn how to use it and then using it frequently enough not to forget how to use it. It's still not natural for me to even remember I have a camera in my cell phone...But I carried a 35mm Leicaflex and 3 lenses around the world for over 40 years... the same one!

Thanks again. WIll see how things work out.
 

swathdiver

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Great advice! Thanks. Haven't bought a used vehicle for probably 40 years. But 60 + grand for a new Yukon seems over the top. Have to spend a lot of time reading the instructions for all that new (to me) stuff like rear camera, side blind zone, cell phone integration, and the whole driver information center. I had the OEM suplied XM radio back then, and on star (never used it or paid for it), and a pretty basic (by todays standards) driver information center. But at the time, it was a big deal. My average for 325,000 miles: 16 mpg .

No GPS at that time, except my Magallan GPS system stuck on to the windshield, with the antenna through the moon roof. Cost me over $1,000 at that time from Costco. But was magic for a guy on the road a lot for business. But I had learned how to use it because it was the same system Hertz first used. All this technlogy is only as good as your ability to learn how to use it and then using it frequently enough not to forget how to use it. It's still not natural for me to even remember I have a camera in my cell phone...But I carried a 35mm Leicaflex and 3 lenses around the world for over 40 years... the same one!

Thanks again. WIll see how things work out.


Most folks complain about the factory navigation but I love it. Just have to figure a way to keep it updated as the last one was 2016. The looks and screen was little different from a Pacifica we rented two years ago so maybe there's a way. I've yet to locate a mapping/navigation company offer an update other than the folks GM contracted with.
 

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