AFM - Hey, Ron - MO or anybody

woodbutcher · Jul 25, 2015

After reading replies to my post about the 5.3L V-8 in my GMC I'm looking at ways to disable the AFM. I've read about Range and Predator and others. What are the advantages and disadvantages? I'd like to know what to watch out for.
Butch

Ron-MO · Jul 25, 2015

I purchased the Range device off ebay (about half what new was). Very happy with it, and my truck stays in 8 cyl mode now, and avg. mpg is around 19, and I drive mix of roads ranging from gravel to two lane to interstate. It now does not hunt gears with the 6 speed like it did. Before when it got up into 6th and dropped to V4, a lot of times it would also down shift to 5th, especially on the smallest grade or headwind on the interstate at 70 or so. That behavior is gone now, and I do not see any negatives to the device at all, and supposedly it will not void the warranty since it does not modify the programming in the ecm, and it is simple to unplug. I leave it plugged in even when the truck sits and it sits for sometimes 2-3 weeks at a time in the basement.

Ron-MO · Jul 25, 2015

oh....in reply to your previous post, I cannot recall when they went to AFM on the 5.3. I have a 2011, and all 2011 models had it. Actually my truck was a very early 2011, and built in July 2010, and purchased in July 2011 so it sat on the lot for about a year. I do wish I had looked more, and purchased a 11 or 12 with the 6.2. Nearly 100 more HP, and heavier duty rear axle, rear disk brakes, and I believe better gearing. But disable of the AFM sure helped mine, and I noticed the exhaust pipe is not nearly as black now since it is no longer killing off half the cylinders.

woodbutcher · Jul 25, 2015

Thanks, Ron, for both replies. The Range is probably the way I'll go. I've noticed the same thing you mentioned about having it hunt the right gear, too. The reason I asked about when they made the change: I traded a 2009 Silverado 5.3 for this 2013. I didn't realize that it had AFM too.
Butch

Ron-MO · Jul 25, 2015

I went with a used one on ebay so if I did not like it, I could likely recover most if not all my $$ for it, and I would not be able to say that about new. I have had it for nearly 2 years now, and never look back, and well worth it, and fuel mileage is same if not improved slightly.

AFM - Hey, Ron - MO or anybody

woodbutcher

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