GM AFM Disabler

[vmax]

One of the many bad things about the Obama era and prior CAFE fuel economy regulations is that Dodge, Ford, Toyota and GM have all had to do some stupid crap to our pick up trucks to get a tiny bit more of fuel milage to help with the CAFE standards

Aluminum body panels, 8 speed transmissions that cost $5000 to repair, load sensing , cylinder shorting software that cuts some cylinders down and the list goes on.

A bad side effect of the GM AFM Active Fuel Management is that when it cuts out 4 cylinders it effects the lubrication of the cam shaft and lifters causing wear.
Used to be you could get 250K miles out of a GM v8, but I have talked to plenty of shops that are seeing them crater at 150,000 because of this.

So, I got to looking into it, since mine has over 40, 000 on it and found that a few companies are making programmers that disable that bullshit and force the engine to run on all 8 cylnders all of the time like it's supposed to.
Many people say that they have had no loss in fuel economy and some say its even better.

I found what I think is the best one, from Range Technology .
https://rangetechnology.com/afm-disabler/

They are $199 and you plug them into the OBD2 port and leave them there. While plugged in, they disable the AFM and if you take your truck back into the dealer for anything just pull it out and it goes back to factory settings.

Good ole American ingenuity.
My advice is not to buy from Amazon or Ebay. Buy from Range or a reputable reseller like Summit or Napa, that way you get an authentic unit and not some ripoff imposter.

I'm excited to see how my truck runs with it and look forward to longer engine life with the AFM disabled.
Anyway, I just thought I'd share what I have learned about this.

 

[Brains]

You usually see about a 1-2mpg increase with AFM active, depending on conditions. Over time that adds up I suppose, but of course it helps GM bump the CAFE average up across the fleet.

When an AFM lifter fails, it's usually not too bad of a repair. Strip the motor down to the shortblock, swap the cam and lifters, and usually do a hard conversion to non-AFM in the process. Any performance shop worth its salt can knock it out in a day.

 

[vmax]

....
When an AFM lifter fails, it's usually not too bad of a repair. Strip the motor down to the shortblock,....

You see...to most people, "not too bad of a repair " and "strip the motor down to the short block" are not 2 phrases that go together!

 

[grasshopperglock]

The way I understand it. Don't turn on cruise control and it doesn't go into the 4cylinder mode. Turn the cruise on and stay at a steady speed. The ECM turns it on. Anytime more power is needed. It turns it off.

My ride has it. Ill be damned if I can tell when it comes on. Some folks say you see a vibration in the rear view mirror. I call BS on that one. Good luck noticing anything.

 

[pronstar]

GM has a poor history with cylinder deactivation LOL

This was a disaster

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[Brains]

I don't know about the 5th Gen Camaro, but on the two GM's I've owned that had AFM there was an indicator you could enable on the dash to show the status (2016 Camaro SS, 2009.5 G8 GT). Cruise control is definitely not the determining factor though, it'll enable any time the opportunity presents.

The transition from 8cyl to 4cyl and back to 8cyl is done quickly and seamlessly on a per-cylinder basis. You shouldn't feel it. If you do, something is generally amiss or you're right on the edge of torque demand where the engine will switch back to 8cyl mode. The easiest way to tell is with aftermarket/modified exhaust - it sounds terrible in 4cyl mode if the exhaust isn't baffled well.

 

[grasshopperglock]

GM has a poor history with cylinder deactivation LOL

This was a disaster

View attachment 138362


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That turd had a single throttle body with two injectors. To turn the cylinders off. They'd have to do it by turning the spark plug. Fuel is still being sucked in. Miami Vice was still on T.V..

Fast forward 30 years. Each cylinder has an injector and coil. The lifters are now electronic. You'd have to experience it. It's pretty cool how they do it.

 

[Brains]

For science.

Lifters are more or less standard hydraulic, with an internal hydraulic locking mechanism. Pressurized oil is fed through the lifter bores to the 8 AFM lifters, which locks them at std. height and allows the valves to be lifted open. When oil pressure is relieved (electronically via an oil solenoid, commanded by the PCM), the locking mechanism releases, \ the lifter rides the cam but a spring takes up the slack between the pushrod and the lifter cup. The valves stay closed, and the PCM also disables the fuel injectors for those cylinders.

 

[grasshopperglock]

Wait till they install AI in cars and trucks. Remember Kight Rider? Take away everything being bulletproof and thats gonna be your future ride.

 

[vmax]

The way I understand it. Don't turn on cruise control and it doesn't go into the 4cylinder mode. ...

Sorry thats wrong, at least on my 2016
In the fuel mileage screen I can see it switch back and forth
Especially when going downhills

 

[grasshopperglock]

Sorry thats wrong, at least on my 2016
In the fuel mileage screen I can see it switch back and forth
Especially when going downhills

Why exactly do you want to turn that function off? What issues is causing to the deliverability? If its saving fuel and yet you have full power on demand. Why turn it off?

 

[Vaquero]

Sigh

 

[vmax]

Why exactly do you want to turn that function off? What issues is causing to the deliverability? If its saving fuel and yet you have full power on demand. Why turn it off?

dude....did you even read the OP?

 

[Dawico]

dude....did you even read the OP?

He has comprehension and retention issues.

 

[Dawico]

I don't know anything about all that AFM stuff but 150k is crazy.

I do know I hate how far the EPA has pushed our vehicles into unreliable heaps of inefficient garbage.

I have about 30k more miles of warranty on this diesel and then it is getting deleted.

 

[TxStetson]

I don't know anything about all that AFM stuff but 150k is crazy.

I do know I hate how far the EPA has pushed our vehicles into unreliable heaps of inefficient garbage.

I have about 30k more miles of warranty on this diesel and then it is getting deleted.

Current production diesels are pretty awesome when you remove the 3 garbage EPA systems on them. Banks Racing currently has the new Duramax pushing 1,000 hp after the EGR delete, straight piped exhaust, and a slight timing change on the injectors.

 

[ZX9RCAM]

Current production diesels are pretty awesome when you remove the 3 garbage EPA systems on them. Banks Racing currently has the new Duramax pushing 1,000 hp after the EGR delete, straight piped exhaust, and a slight timing change on the injectors.

I'm having a hard time believing that's all they did to hit 1000hp.

 

[stdreb27]

I'm having a hard time believing that's all they did to hit 1000hp.

Yep.

But the premise is right. And it probably gets 25% fuel economy too.

 

[pronstar]

I don't know anything about all that AFM stuff but 150k is crazy.

I do know I hate how far the EPA has pushed our vehicles into unreliable heaps of inefficient garbage.

I have about 30k more miles of warranty on this diesel and then it is getting deleted.

I regret selling my 07 Ram 5.9 CTD.

All it had was a cat.
And a goofy cam for in-cylinder EGR.
Both easily rectified


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[mitchntx]

08 Tahoe
149K miles

Got the dreaded ticking lifter noise.
Tried all the youtube quick remedies.
Nothing worked.

Brains is correct ... stripping an LS motor to the shortblock isn't a big deal. But I did the math ...

Cam, lifters, push rods, head bolts, gaskets, valley tray to remove AFM was $1200.

Then the might as wells surface.

Heads are off, should true them and replace seals.

Timing set of course.

Tackle that pesky oil pickup o-ring. While I'm here, replace the oil pump.

I'm not going back with the old water pump either.

Finally belts and hoses.

So now I'm close to $3k in and at the end of the day, I still have 150k motor.

So the question is ... do I trade it with an audible engine noise and take a bath or crate motor it and drive it for 5 years?

I installed a GM crate motor AND a range module.


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