So I'm new to my LMM, had it since may, but have been curious what this is.

At idle in park, the truck idles normal, then seems to get a loader deeper tone (which I love, how do you get it like that all the time??!) then it a few seconds later completely muffle itself like someone put a cap on the exhaust tip?

Had DPF delete is it cycling something?

It is the vanes in the turbo changing geometry. The lower, deeper tone is when the vanes are open and the turbo is not spooling.

Turbo vanes cycling (self test) as stated. You can maintain the deeper tone with EFI Live

Turbo vanes cycling (self test) as stated. You can maintain the deeper tone with EFI Live

Is it testing? I've always wondered what triggered it. On my custom tunes, I sometimes hear mine cycle. It always does a cycle at startup on all tunes.

With the exhaust and turbo upgrade, mine sounds like a turbine engine starting. At stop lights, I see people looking up like planes are flying over. :lol:

Only way to do it is with EFI Live? Its kinda annoying as it will do it a few times while sitting there standing next to it, and def draw attention when trying to talk to someone next to ya. They are like what was that, I say, hell I dunno, beats me?!:confuzeld All that money in the truck and I look like I don't know what I'm talkin about... At least I have an answer but why does it do it so frequent?

mine doesn't do it very often. Every couple days it seems.

Turbo vanes cycling (self test) as stated. You can maintain the deeper tone with EFI Live


Care to share what to change in EFI Live?

And what effects will it have on the motor by changing it from the hiss to the rumbling sound at idle?

-Fred