Tuning Out AFM

Hello, Everyone

I've been gone for awhile, but finally purchased another Avalanche a couple of weeks ago. It's an '08 Deep Ruby Metallic LT3 Z-71 Dream Machine.  I love everything about it, except for one thing: The Active Fuel Management is really starting to annoy me.

I've researched AFM/DOD a little for a couple of years.  It's a fascinating idea, but I believe it has the potential for doing more harm than good, in the long run.  

Already know there are ways to disable AFM with a tuner.  What I don't know for sure is whether I would be able to return the ECM to its original factory state, in the event I would have to take it to a dealer within the remaining warranty period?

Are the dealerships capable of detecting whether the programming was altered at some point.  If so, can one of you experts explain the technical reason why this would be so? Thanks for your help!

   

what year is your truck, makes a difference

The only way we know if its been altered is if the programer is in the truck when you bring it in, or if we need to reprogram the ecm. It will tell us the current calibration is unknown.

Thanks for replying, guys.

Avalanche is an '08.

If I turned AFM back on (returning calibration to its original state,) before visiting the dealer, would it then be able to recognize the calibration? 

I wouldn't want any type of trail left behind.  Didn't know if the system created an event log that could be tracked.

Thanks, again, for your help!

Nick

any change not made by gm will show up

Understood.  Thanks, again.

Nick

No problem. Best bet it to wait till its out of GM warrenty and get it tuned aftermarket.

When I tuned...had tuned...my then new '08 I bought out my stock ECM/TCM and kept them under the rear seat ready for reinstall for this same warranty reason. Now out of warranty I had them flashed for a second, premium, no AFM tune.

hows your MPG without AFM?

krazycarguy said:

hows your MPG without AFM?

Click to expand...

I think it's a bit lower but it's difficult to tell for sure at this point. I ran in the new 91/93 octane tune for a couple/three tanks to get a baseline and then had AFM flashed off. I'm getting lower fuel mileage, but we're in a seasonal change and my city/highway mix has been a bit different. It's also a low use locally vehicle.

If I had to swear to something, I'd claim a loss of 0.5 +/- mpg highway and nada on surface streets.