This is whacked but my turbo is spooling up at idle. Start the engine w/ trans in park, stand by exhaust, nice low note "no-boost" rumble for about 15 seconds (+/-), turbo then spools sometimes sounding like 100k rpm! Then intermittently note drops instantly to low rumble and then Spools back up, sounds like vacuum cleaner hiss. This also happens driving and stopping at lights or drive throughs with trans in D. Have had this prob since new in '05.
Sucks the fuel at idle. Straight round trip highway mileage is 13.7 tops calculated with refuel on same pump, "full" cuttoff method and gps. Many tanks and different cruise settings with no change. Tried disconnecting egr, 15 miles a tank better with significant improvement in responsiveness.
Is this a Turbo/electronic feed-back/control prob or fuel delivery prob? Have had to dealership, one place flashed the computer with no change and another place said "I'll have to research it" with nothing done. If and audio sample will help I can try to load, link,or send an Mp3 or WAV. This prob did exist prior to removing Cat and Muffler.
2005 LLY 3500 Dually CrewCab 2 wh dr, 3.73, 36k miles on ODO, Mobil 1 oil, Bone stock everything but Cat and Muffler removed and straight piped for troubleshooting (this improved mpg 40mil/tank).
WOW, Does ANYONE have an idea? THE DEALERSHIPS SURE DON'T!!!

not sure why your mileage sucks but that sound your hearing is normal in all LLY's. VVT just doing what it does, changing vane positions and that changes pitch

Normal

Yup, normal VVT ops.

.

check the video section there is a guy with an exhaust clip Volant 4" 304SS exhaust with 5" double walled tip and MBRP catless downpipe on an LLY (http://video.dieselplace.com/search/exhaust/0/3F17C71C-9A80-40E1-8B32-9EDD587C854F.htm) and see if it sounds like that. if so its normal. not sure on the mileage some trucks will do better then others.

Normal. I worry when it doesn't make the VVT noise on startup.

Not sure why 8,000lb duallies don't get better mileage.

:banghead: missed the part where it said dualie but that would more than likely explain your gas mileage problem.

Normal. I worry when it doesn't make the VVT noise on startup.

Not sure why 8,000lb duallies don't get better mileage.

What might the problem be if it doesn't make the VVT noise?

Thanks guys! It does sound just like the video. I still can't understand why they would program the turbo to spool at all at idle though!

turno isn't creating any boost when it's doing it's normal VVT thing. least not enough to register on a mechanical gauge.

Now to find a way to make it rumble all the time.......... or whistle if you like........

Your mileage is about the same that i get. 13.5 -14mpg running empty. However I did get 6.6 mpg last weekend(hand calculated), towing about 16000 lbs., with average speed between 65-70.

What might the problem be if it doesn't make the VVT noise?

Stuck vanes PERHAPS. Emphasis on perhaps. My understanding is that the VVT fluctation @ idle is for building exhaust pressure to keep the CAT hot at idle. SO, perhaps no fluctuation is the result of corrupted programming that is responsible for keeping the cat hot, or perhaps the vanes are stuck. All this being said, I notice more rapid fluctuation in cold weather than I do in summer. I put my straight pipe back in last week, and haven't heard it fluctuate yet, but recall it going up and down when it was straight piped last November. Not concerned in the least because I can here is going up and down when I drive.

Thanks guys! It does sound just like the video. I still can't understand why they would program the turbo to spool at all at idle though!

it does this function to create backpressure to aid in engine warm up (for emissions purposes i would imagine), noraml like everyone said, mine does it.