Sound Change???????

[Super 05]

Was pulling about 6000lb tonight no big deal. Unloaded then started to pull out from a stop sign then heard a major change in the way the engine sounded. Still ran ok but power wasn't as much as usual. No excessive smoke. Fuel mileage dropped like a rock! Could watch the miles till empty drop 10 miles in about a 2 mile stretch. Was thinking I blew a boot but all the boots are tight. No splits in the boots. Could it be the turbo vanes? And how do I know for sure?

 

[bushpilot]

scan for codes.

also if the vanes are STUCK youll WONT hear a change in PITCH
of the exhaust.

ive got the turbo back mbrp w/ test pipe so mines a little easier
to hear but...when i 1st start the truck i have a deep rumble...only
a couple of seconds after the exhaust note changes to a "hiss" like
a jet engine.

the pitch change is from the vanes moving toward a more CLOSED
position once oil pressurizes the VGT Solenoid/Valve --> Page 35: Air Management System

if the problem IS VGT/VANE related it might not be the VANES themselves
it could be a problem w/ the VGT/Solenoid Valve

 

[95_stroker]

Could it be the turbo vanes? And how do I know for sure?

Are you making boost?

 

[Super 05]

Yes building boost

 

[Super 05]

Unplugged the wire going to the VGT control valve tonight and the sound went away. Plug it back up and guess what...the sound came back. Does that mean the VGT Control Valve is bad? Hasn't thrown a DTC yet.

 

[bushpilot]

the valve SHOULD change the pitch...and are you CERTAIN you
unplugged the VGT ? its not easy to get to.

and how may i ask did you check it for codes ?

 

[Super 05]

NO not certain it was the VGT. I unplugged whatever it is on top of the turbo that has a two wire plug going to it. That stopped whatever the sound is that I am hearing. Soon as I plugged it back up, sound came back. Pulled the codes with The Edge

 

[bushpilot]

what happens if you leave "the edge" disconnected ?

 

[Super 05]

"The Edge" is completely removed from the truck and is still doing the same thing.

 

[Kleetus]

Is the VGT position sensor in the same plug as the actuator itself, or is it on a different connector? I never looked, and it's raining lots of small mammals right now...