'97 F350 Powerstroke w/auto. When starting truck when cold, the truck fires up just fine. But when you drive, there is no power and a ton of black smoke pours out. As soon as the temp gauge hits the 'r' in 'normal', it's like someone threw a switch and the truck runs fine. If you plug the truck in the night before, I don't have the problem, it starts and runs right away. Any ideas?
Diesel engines get all there power when they are hot. A cold engine can't burn the fuel because it take pressure and heat to combust the fuel. Thats why you get black smoke, all of the fuel is not burning. Best bet if you don't plug in the heater over night, is to start it up about 5 to 10 min. before leveing and it will have time to get up to operating temp and give you full power quicker.
I don't know about the black smoke, but when the engine is cold the exhaust back pressure valve is activated to help warm up the engine. You should never really work the engine when it is cold anyway. As far as the black smoke, check your air filter.
Do you have an oil consuption problem?
The symptoms you described are classic of bad injector seals. My mechanic went over this problem w/ me just the other day. He actually said "is it down on power, especially when it is cold?". He then went on to state that would mean the that there is an injector seal problem.
There is not really a oil consumption problem...it uses about a quart between changes. After the temp guage comes up, the truck runs fine but until then, just no power, and if you step on the gas, black smoke comes out. The fastes the truck will go until it warms up is about 30 mph. I have not noticed a whistle in the exhaust during this, but I will kill the butterfly when I get home and see if this works for in the morning.