question on MPG before and after AFM delete

[tiktok4321]

Another source of failure from what my mechanic told me is the lifter tray. These plastic trays can crack and cause the lifter to rotate, getting stuck.

 

[iamdub]

Another source of failure from what my mechanic told me is the lifter tray. These plastic trays can crack and cause the lifter to rotate, getting stuck.

Good point. It's cheap insurance to replace these, AFM or not, when the heads are off and torque their retaining bolts to spec to prevent cracking them around the bolt hole. It's not that sensitive of an issue, but there are plenty of gorilla-handed mechanics.

 

[the highlander]

anyone on the forum do programming? Anyone local to Michigan, Detroit or surrounding area?

Yes I can do it.. I am located in michigan. PM for info.

 

[conchasjim]

Well, it looks like I have a collapsed lifter on the number 6 cylinder. I've had a superchips tune with the tow haul tune which includes a AFM delete. I believe it does, as I haven't seen the prompt when it would go into the V4 mode in years.
With that in mind, it seems you can still have problems even when AFM has been deleted. So, what's the point in deleting it?
Also, if I replace all the lifters with ones that don't allow AFM, i.e. Collapsible lifters, do I still need to run a deleted AFM tune?

 

[swathdiver]

Well, it looks like I have a collapsed lifter on the number 6 cylinder. I've had a superchips tune with the tow haul tune which includes a AFM delete. I believe it does, as I haven't seen the prompt when it would go into the V4 mode in years.
With that in mind, it seems you can still have problems even when AFM has been deleted. So, what's the point in deleting it?
Also, if I replace all the lifters with ones that don't allow AFM, i.e. Collapsible lifters, do I still need to run a deleted AFM tune?

Less wear and tear is the point of tuning it out but it is still best to remove the system for ultimate reliability. If you're going to delete it, you must run a tune with it disabled or it'll throw codes. You must get a new camshaft, non AFM. When you start a new thread about collecting parts and selecting a cam, remind us of the year of your truck.

 

[PG01]

What he said^^^

 

[iamdub]

Well, it looks like I have a collapsed lifter on the number 6 cylinder. I've had a superchips tune with the tow haul tune which includes a AFM delete. I believe it does, as I haven't seen the prompt when it would go into the V4 mode in years.
With that in mind, it seems you can still have problems even when AFM has been deleted. So, what's the point in deleting it?
Also, if I replace all the lifters with ones that don't allow AFM, i.e. Collapsible lifters, do I still need to run a deleted AFM tune?

You disabled it with your tune, but didn't delete it which is going into the motor and removing the components. As James said, it's a midpoint way to hopefully buy you more time by not letting the system activate. It's better than nothing, but the crappy lifters are still in place and are still prone to failure, as you have experienced. Do you mean that your Superchips tune only disables AFM when in Tow/Haul mode?

 

[PG01]

You disabled it with your tune, but didn't delete it which is going into the motor and removing the components. As James said, it's a midpoint way to hopefully buy you more time by not letting the system activate. It's better than nothing, but the crappy lifters are still in place and are still prone to failure, as you have experienced. Do you mean that your Superchips tune only disables AFM when in Tow/Haul mode?

Thats a first......

 

[iamdub]

Thats a first......

What is?

 

[PG01]

What is?

Go back a few pages in this thread when you stop ******’ with Christmas lights....

 

[sumo]

It’s not a MPG gain it’s really more of a how much oil you retained because you disabled that ****** system

 

[randeez]

Well, it looks like I have a collapsed lifter on the number 6 cylinder. I've had a superchips tune with the tow haul tune which includes a AFM delete. I believe it does, as I haven't seen the prompt when it would go into the V4 mode in years.
With that in mind, it seems you can still have problems even when AFM has been deleted. So, what's the point in deleting it?
Also, if I replace all the lifters with ones that don't allow AFM, i.e. Collapsible lifters, do I still need to run a deleted AFM tune?

you will also need to replace the cam, the lobes on the stock cam are ground to be used with afm lifters.

 

[iamdub]

Go back a few pages in this thread when you stop ******’ with Christmas lights....

Nah, I'ma stay here, Griswolding this muddafugga.

 

[iamdub]

It’s not a MPG gain it’s really more of a how much oil you retained because you disabled that ****** system

I forgot all about the oil savings in mine! This should be interesting in 3,000 more miles.

BTW, My MPG so far is two tenths higher at 16.4 since having it disabled. But, it's only been 2 days.

 

[Doubeleive]

geez I have a heavy foot, 10.6mpg is about as good as it gets for me city/hwy combined, I think it cropped up with 12-14 on long highway drives once

 

[swathdiver]

What were those Denalis rated for, 12 city 19 highway? At a constant speed between lights in city driving, mine shows 23-26mpg between 40 and 45 mph. I have my truck's original window sticker and the mileage ratings are blank. Can't look it up on Fuel Economy dot Gov website either. That being said, the mileage actually improved some with the tune and turning off AFM.

 

[Doubeleive]

I think mine is rated for 12/18 but im not 100% sure off hand (awd) takes it down a notch right off the top

 

[conchasjim]

Ok, now I'm really confused. Seems the quick and easy way is to just replace the AFM lifters with new ones, replace the trays and leave the cam? Then just run my superchips tune with the AFM feature disabled? Then sell this POS Chevy and buy a Toyota? LOL . I love the Tahoe, have had 3 older ones, but what a POS Chevy this turned out to be. And it only has 65K on it. NIGHTMARE?....

 

[iamdub]

Ok, now I'm really confused. Seems the quick and easy way is to just replace the AFM lifters with new ones, replace the trays and leave the cam? Then just run my superchips tune with the AFM feature disabled? Then sell this POS Chevy and buy a Toyota? LOL . I love the Tahoe, have had 3 older ones, but what a POS Chevy this turned out to be. And it only has 65K on it. NIGHTMARE?....

You can replace the AFM lifters with new AFM lifters and you'll be back to where you were, assuming the collapsed lifter is the only failure/damage. This will leave the AFM system usable should you or a new owner want to return the tune to stock, or keep the Superchips tune and enable the AFM.

Or, if you want to keep the Tahoe and while you're in there replacing lifters, replace them with regular/non-AFM lifters and take a few steps more and replace the cam with a stock or mild performance cam. I think there's another AFM part you'd need to replace with it's non-AFM counterpart- maybe the valley cover?

Deleting AFM 'should' make your motor just as reliable as the Gen3 version.

 

[conchasjim]

Less wear and tear is the point of tuning it out but it is still best to remove the system for ultimate reliability. If you're going to delete it, you must run a tune with it disabled or it'll throw codes. You must get a new camshaft, non AFM. When you start a new thread about collecting parts and selecting a cam, remind us of the year of your truck.

Mine is a 2007 LTZ, 2WD, 65k miles