Hissing Noise In Exhaust

[SULLY1]

I Have A 2002 7.3 W/ Western Diesel Ram Air, Superchip Programmer, & Newley Installed S/s 4" Turbo Back Exhaust. Since I Installed The Exhaust When The Engine Is Cold Started There Is A Loud Hissing Noise Coming From The Exhaust. I Beleive It To Be The Waste Gate But Never Noticed It Before. If You Tap The Accelerator It Will Stop But Will Start Again. It Stops After Warmup. Any Ideas?

[Jon]

when it is cold in the mornig. It makes a Sheeooo Sheeooo noise. When you tap the pedal it goes away only to return till the engine is warm. It's the butterfly valve.

[Jon]

But if it didn't do that before you got yourself an exhaust leak.

[SULLY1]

Not An Exhaust Leak, Whats The Fix For The Butterfly Valve?

[00powerstrokin]

that is normal. you can't really hear that with the sotck exhaust. it does that when the temperature is below 35 degrees to help warm up the truck. it closes the exhaust backpressure valve which blocks the exhaust creating the hissing noise. as long as it stops when the truck warms up it is normal. mine wnet out and it would hiss all the time if it was below 35 degrees, so i wired mine to a switch and i use it as an exhaust brake now.

[Jon]

And mine is loud as %#*& in the morning now. Step on the pedal and bye bye!