AFM / DOD Delete

[2001 TX Tahoe]

I’ve read some about this topic but need some educating. I understand there are components (lifters?) that are responsible for switching between V4 and V8 modes. I've also read there is an OBD II module to override this so that it stays in V8 mode. Also read this is just a band-aid. So, am I understanding this correctly? Is there one or are there more modules? Is there is specific one that is recommended? Or big picture, is this recommended at all? And if it the lifters are no longer functioning, how can they still fail, i.e. how is it just a band-aid fix? Or is something else failing? For reference, I have a 2016 Yukon, 5.3L, 99,000 miles, no motor issues. Just trying to get in front of a potential problem.

 

[Marky Dissod]

Merely disabling cylinder deactivation / V4 mode ...
You can buy a glaiyd plug in type thingy that just plugs into your OBD2 port.
So long as it stays plugged in, permanent V8 mode. Pull it off, V4 mode becomes available again til plugged back in.

A far better method of disabling V4 mode - worth every extra penny - is to get the ecm tuned.
Besides disabling V4 mode, several other things get addressed.
The end result can include more MpG, more smiles per gallon, more durability / longevity, additional functionality ...
Ask the tuner what they can and cannot do, then check back with us to see if our bs detectors go off.
BlackBear tuning is highly recommended here.
There are several other highly respected tuners who have maintained stellar reputations for many years (see my sig).

However ...

 

[Marky Dissod]

Physically deleting cylinder deactivation hardware ... (We are NOT discussing Cadillac's V8-6-4!)
Before V4 mode, hydraulic lifters simply did their simple job, well, for 250,000 miles or more in many cases.
In other words, they were very well designed to reliably do one thing.

Then came V4 mode in the late naughties.
8 of the simple one-mode lifters (out of 16 total) had to be replaced with two-mode lifters.
These lifters respond to changes in oil pressure directed by a Variable Oil Lifter Manifold Assembly.
In V8 mode, they are swollen. In V4 mode they go flaccid.
The extra hardware that allows this variable modality was neither designed nor materially specified to be as robust as the one-mode lifter.
After about 15 years, V4 mode lifters have earned (?) notoriety for failing far more often than one-mode lifters.
(They also don't like excessively leadfooted drivers who spend too much time at very high RpMs.)
Changing oil and filter more often than GM recommends helps them last longer, but they'll just never last as long as their simpler ancestors.

Simply put, the long-term solution is to remove & replace the dual-mode lifters with one mode lifters.
A few other things need replacing as well, like that Variable Oil Lifter Manifold Assembly; it gets replaced by something far simpler as well.
The end result is a V8 that will never physically impersonate a V4 ever again.

 

[Marky Dissod]

For reference, I have a 2016 Yukon, 5.3L, 99,000 miles, no motor issues ... YET ...
Just trying to get in front of a potential problem.

Disabling Engine Half@$$ (plug-in or tune) will delay the failure of the two-mode lifters.
It also helps to change your oil more often than GM recommends, and to use a larger oil filter.
Same goes for your air filter. Keeping things clean is CRUCIAL.
However, the two-mode lifters can still eventually fail, even with Engine Half@$$ disabled.

That's THE major reason why people do lazy cylinder hardware deletes.
To be clear: there have been enough two-mode lifter failures in engines with Engine Half@$$ disabled,
that a preemptive lazy cylinder hardware delete is strongly recommended for anyone with long-term plans.

Long story short:
everyone should disable Engine Half@$$ (or Cylinder Confusion) at first opportunity to lower the odds of a lazy cylinder hardware failure.
To permanently avoid any possible failure, delete lazy cylinder hardware at first convenience.

 

[2001 TX Tahoe]

Disabling V4 mode (plug-in or tune) will delay the failure of the two-mode lifters.
It also helps to change your oil more often than GM recommends, and to use a larger oil filter.
Same goes for your air filter. Keeping things clean is CRUCIAL.
However, the two-mode lifters can still eventually fail, even with V4 mode disabled.

That's THE major reason why people do V4 mode hardware deletes.
To be clear: there have been enough two-mode lifter failures in engines with V4 mode disabled,
that a preemptive V4 mode hardware delete is strongly recommended for anyone with long-term plans to keep it.

Long story short:
everyone should disable cylinder deactivation at their first opportunity to lower the odds of a V4 mode hardware failure.
To permanently avoid any possible failure, delete V4 mode hardware at first convenience.

This is all very helpful. Thank you.

Ballpark, what should an ECM tune cost from a reputable tuner?

Deleting the hardware... is this a "tear the engine down" type of mod? How expensive and complex?

Finally, what happens when the dual mode lifters fail?

 

[SpyShops212]

Just drive in manual 9

 

[Marky Dissod]

Ballpark, what should an ECM tune cost from a reputable tuner?
Deleting the hardware ... is this a "tear the engine down" type of mod?
How expensive and complex?
Finally, what happens when the dual mode lifters fail?

Someone needs to answer these questions in better detail than I.
I don't know as much about Gen 5 direct injection V8s as I do about Gen 3 & Gen 4 V8s.

 

[tom3]

One of these springs lets go and it all gets bad real quick.

 

[tom3]

As opposed to a standard hydraulic lifter:

 

[Marky Dissod]

If I'd seen pics like these in '05, I'd've been looking for how to defeat this folly in '06.