When Does The Active Fuel Management Kick In

[emerson1]

I have a 2008 Silverado Extended cab Texas V8 5.3 liter. I was wondering at what speed do you have to get to for the AFM to kick on?

[wurgs]

Didn't check all the time but noticed it on at 20 mph one time. Disabled now thanks to Diablo

[66nova]

It isn't activated at a mph, it's based on throttle position.

 

I think I remember something like less than 5 or 10% throttle and it will kick in.

[emerson1]

Ah, so the cruise control set at 65 will let it kick in. I had heard you had to be going 70, good to know you don't.

[06MonteSS]

actually... it DOES matter what speed you're at as well...

 

it goes by speed, rpms, throttle position, and vacuum pressures...

 

also depends on what gear you're in... if you're in 1, 2, or 3, it won't come on at all... have to be in D...

 

and, have to be between 20-75 (or may even be 80) mph....

 

if you're over 3200rpm, it won't kick in either...

 

 

here's some info about the DOD system...

http://www.ls1tech.com/forums/ls4-front-dr....html?p=5322427

[stormrider]

I don't know all of the times but I can tell you that it would always kick in at 48 mph on a straightaway. It would asways cause a dash vibration that drove me nuts.

Thanks to Justin it never kicks in anymore

[06MonteSS]

exactly... one of the first things I do in my custom tunes for people is to just completely disable that altogether.... ;-)

[nickvrebel]

the actual tune from the factory says you must exceed 11 mph, engine must be running for 30 sec, engine coolant temp must be at least 97* and then you get in to requirements for the throttle position sensor, vacuum, etc.

[emerson1]

Dang only got 16.5 mpg on my first fill up and calculation of it. Kinda surprised actually as there was a 270 mile trip where the AFM would have been kicked on.

[88K5]

Had it on my 08 Avy and loved it. It would shut down to 4cyl. when ever the load on the engine was reduced. The DIC had a display that would show instant fuel economy and it showed V-8 and V-4 when it came on.