cold weather startup???

[toddster]

first winter with my 02 psd dually, and had a question for the guru's
at very cold weather startup...she starts like a champ, but soon after the idle bumps up to 1100 rpm and it sounds like the exhaust is restricted or bypassed. If I touch the fuel peddle, it kicks right back to normal...I assume it is a warm up choke.
The main info I would like to know, is when I leave after 3-4 mins of warmup, and at regular almost idle acceleration it sounds like the truck bypasses the turbo as I hear a fweshing (air blowing) sound at the passanger side, If I push a little harder on the peddle it goes away, and once it is up to regular operating temperature, all returns to normal.

is this a feature powerstrokes have so that at cold temperatures the turbo will not compress too much to damage the engine?

thanks to all info
cheers
Todd

[SMKSTAX]

This is probably just your EBPV or exhaust back pressure valve. It closes to aid in engine warm up. Perfectly normal.

[toddster]

thats what I thought.....cool thanks!!!

[720Deere]

Rick has you covered. It's the EBPV and it's normal. Many people remove it because it's a restriction in the exhaust system or you can wire it up to a switch and use if as an exhaust brake.