Tunes And Afm

jdg2 · July 1, 2009

Anyone else think that AFM is way more noticeable with a tune than it was before the tune. I had some adjustments made to my tune this past weekend and thought about turning off AFM but didn't. Now AFM seems more noticeable than ever. Stays in V4 mode a little longer but when it switches in and out it seems way more noticeable. Was trying to avoid turning it off (mileage) but may have to give in. I hate that surge/chug... I know, we're beating the dead horse again.

2005LT · July 1, 2009

There seem to be two different sides to this J.D. Some claim that AFM is more noticeable while others experience no change or feel it even less. I'm sitting on the fence about whether to turn AFM off or leave it on when I get a tune. The thing is, there seems to be a lot more folks on here who are in your camp and had to turn AFM off.

66nova · July 1, 2009

Anyone else think that AFM is way more noticeable with a tune than it was before the tune. I had some adjustments made to my tune this past weekend and thought about turning off AFM but didn't. Now AFM seems more noticeable than ever. Stays in V4 mode a little longer but when it switches in and out it seems way more noticeable. Was trying to avoid turning it off (mileage) but may have to give in. I hate that surge/chug... I know, we're beating the dead horse again.

Justin says he see's this quite a bit with the 6.0L. For mine, my AFM is actually better then when it wasn't tuned. Right after I got the tune it was horrible especially when it was cold. But now it is a lot better then before. Really the only time I feel it is when I am bucking a hard wind or going up a hill and it trys to kick and immediately kicks out.

I am too considering turning it off though for one reason. I tow a lot and I hate it kicking in while I have the trailer on. I like AFM 85% of the time, but I bought a Vmax to for the pulling power of full 6.0. I don't want a 3L pulling my trailer.

VMax2007 · July 1, 2009

Mine was 100% undetectable before the tune. But very noticeable after. It is now off and I do not miss it and have seen ZERO reduction in gas mileage.

It's staying off!

Stevens03 · July 1, 2009

I turned mine off with diablo,... and will continue to have it off when I get a custom tune

On my drive to work (15 min. drive) I tested it to see if I got better mileage on verses off, and saw no difference. Thats why I left it off.

2005LT · July 1, 2009

Robert, it sounds like yours stays on a lot more of the time. Did Justin up the threshold percentage for you? I can only get AFM to stay on in the first 1/2" of pedal travel or so. Even at a constant 40 mph, I can't keep it in 4 cyl mode. Pulling a trailer...no way mine would ever switch to V4 unless coasting down a good size hill.

jdg2 · July 1, 2009

Anyone else think that AFM is way more noticeable with a tune than it was before the tune. I had some adjustments made to my tune this past weekend and thought about turning off AFM but didn't. Now AFM seems more noticeable than ever. Stays in V4 mode a little longer but when it switches in and out it seems way more noticeable. Was trying to avoid turning it off (mileage) but may have to give in. I hate that surge/chug... I know, we're beating the dead horse again.

Justin says he see's this quite a bit with the 6.0L. For mine, my AFM is actually better then when it wasn't tuned. Right after I got the tune it was horrible especially when it was cold. But now it is a lot better then before. Really the only time I feel it is when I am bucking a hard wind or going up a hill and it trys to kick and immediately kicks out.

I am too considering turning it off though for one reason. I tow a lot and I hate it kicking in while I have the trailer on. I like AFM 85% of the time, but I bought a Vmax to for the pulling power of full 6.0. I don't want a 3L pulling my trailer.

Maybe I just need to let the new settings settle in a little bit longer. It's funny when Justin is riding with you everything seems great, then AFM rears its ugly little head . Oh well at least I only live about an hour away from Justin. I bet he doesn't feel the same way. Although I have to admit he does seem to like what he's doing and he is very good at it.

2005LT · July 1, 2009

Well, at least you're not too far away and can have him change it for you. Let us know if it improves at all with a bit of driving. I'd like to make it work yet but at 2500 miles away it will be harder to make changes.

VMax2007 · July 1, 2009

Well, at least you're not too far away and can have him change it for you. Let us know if it improves at all with a bit of driving. I'd like to make it work yet but at 2500 miles away it will be harder to make changes.

Justin street-tuned my truck in Nov 08 and adjusted AFM to activate/stay on longer and it (the surging) never got any better. I gave up and turned it off in March.

SparkySparks · July 1, 2009

I have a 5.3L and I left mine on until I started making a longer drive to work. I found with the longer drive it would kick in and out a lot more and strated to bug me. I have noticed no drop in fuel milage and in fact its gotten better but I think thats due to me have a longer drive. I was doing 90/10 City/Highway now its more like 75/25, I also drive about 75 when on the highway.

Nick The Great · July 1, 2009

Justin bumped up my AFM threshold a little bit. I can't say it's on much more than it was before. But I certainly can't feel it more than before. 99% of the time, the only way you'd notice it is on the DIC screen.

If I ever had him redo anything, I'd probably have him shut if off, because I really don't think it saves more than a cup of fuel.

I have the 5.3L FWIW.

2005LT · July 1, 2009

Alright then, sounds like it's gotta go. Too hit-or-miss to risk leaving it on.

SparkySparks · July 1, 2009

I also didn't like how the exhaust sounded at highway speeds when it would go into V4 mode.

66nova · July 1, 2009

Robert, it sounds like yours stays on a lot more of the time. Did Justin up the threshold percentage for you? I can only get AFM to stay on in the first 1/2" of pedal travel or so. Even at a constant 40 mph, I can't keep it in 4 cyl mode. Pulling a trailer...no way mine would ever switch to V4 unless coasting down a good size hill.

No, I think it is just the power difference after the tune. It pulls so much better. It doesn't do it as much when I have a heavy load, but when its a light load, it sucks.