AFM problems?

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BIGGERSHAFT94

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Alright so im getting a tune tonight on the hoe and i was wondering why everyone suggests ditching the Active fuel management?
 

MichaelSE

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There are a few reasons that people get rid of it.

1. AFM is documented to destroy lifters more often than I'm comfortable with. Google "AFM lifter failure."

2. AFM is documented to cause oil consumption.

3. For those with aftermarket exhausts, the note changes significantly when the truck is in V4 mode.

4. Some people experience shuddering/shaking with the transition from V8 to V4 or V4 to V8. This wasn't an issue with my Suburban but I've seen a few posts on the forum about it.

5. Torque available more immediately when you need it; as opposed to stomping the pedal and waiting for the engine to transition, then delivering power.

6. Some people (myself included :D) believe a half ton SUV should have a V8. All the time.
 

Jason_S

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With AFM, you get:
-Increased oil consumption. some have seen close to a quart every 1k miles.
-crappy sound when in 4 cyl mode if you have aftermarket exhaust
-some folks claim that AFM doesn't actually improve mileage.

Several people have experienced cam shaft and other engine failures as a reported result of running AFM. I had almost 170k on the original engine and internals, but I don't know if I was the exception or if those that experienced failures are.

With AFM disabled you should see:
-reduced oil consumption. (As reported by many folks on this and other sites.)
-no 4cyl mode to make crappy sound with aftermarket exhaust.
-some have claimed better fuel mileage, but I think that actually depends on useage, tune and driver's right foot.
-less worry about AFM related components causing engine failure.
-with the AFM component delete, a larger range of cam shaft choices.
 

MichaelSE

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Yeah, the gas mileage loss from deleting AFM is negligible. Even with my 6.0, I can average 19 or 20 mpg on a long flat highway (provided I can keep it under 70). With AFM it might have been 20.5 if I was lucky.
 

sumo

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Afm looks good on paper but in the real world it's headaches. Mine started shaking when trasistioning from 4 to 8. When I'm 4 cyc mode, the exhaust wasn't drastically different, but you could tell when it does. Using it as a everyday vehicle, it can get annoying.
Getting rid of Afm was probably on of the best things I don't for my truck.
 
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BIGGERSHAFT94

BIGGERSHAFT94

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Yeah, the gas mileage loss from deleting AFM is negligible. Even with my 6.0, I can average 19 or 20 mpg on a long flat highway (provided I can keep it under 70). With AFM it might have been 20.5 if I was lucky.
i highly doubt mine would do that well anywhere close to 70. Mine has 4.10s and gets 20.5ish at 50 and drops to 19.3 when im at 60 lol. I have yet to get it out on the interstate but i dont imagine the milage is very good lol. Also it has stock exhuast so it never really made any different noise when it hit v4.
 

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