Hellow fellows,I'm pretty new around here but could use some help.I have a 97F450 that I bought a few mounths ago.After inspecting the turbo I noticed something like a butterfly valve wired in the open position.The truck runs great on flatland and inclines,but once you start going downhill the truck starts to smoke a greyish smoke and motor starts to stumble.If you get on the throttle it clears up.Also smoke smells like almost raw fuel is being dumped out of tail pipe.Not sure if it has any thing to do with the valve being tied up or not.Any help would be much appreciated!

 

That valve that is wired open is your exhaust backpressure valve. Basically when its hooked up and functioning properly it is used to aid in warming up engine when its cold out. It is quite common for it to get stuck open or closed due to soot inside the pipe so most people usually gut the valve out or wire it open. Sounds like your problem is injector O-ring related. Someone will come along soon and be able to verify that for ya.

later,luke

 

I have also heard, not confirmed this but that gray haze at deceleration could also be a sign of turbo seals going out, how it works no clue.

dito on what luke said about the valve

Diesel Rod

 

Thanks guys for the reply,I intend to check it out this weekend.