7.3L diesel smokes like a train (black) and has no power, what to look for first?

Check the turbo see if it is working. It can cause this problem.

First check the air filter, then fuel filter, see if water seperator bowl has dirt or water in it, if all these are ok then I would see if the injection pump has an adjustment on it for fuel (some do). If so it is set too rich, some people turn the fuel flow up on them to get more power but it causes excess smoke from tailpipe. If it doesn't have an adjustment on it or you have turned it back and still have the same problem, the timing could be out of adjustment, Have you replaced the injection pump recently or turned it? If so, the timing is off. If you haven't, then the inj. pump may be going bad or an injector. Test the injectors by loosening the fuel line at the top of one injector at a time while engine is running, the eng should run rough each time you open and close a fuel line until you get to the one that doesn't make it run rough, then thats the bad one. older 7.3's were easier to diagnois then new ones with the electronics. Does it have a turbo? If so, pull the tube off the front and start the engine, have someone stand clear but to look inside of turbo while you rev up engine to see if the turbo spools up inside, if it doesn't, the turbo is bad and needs replacing. good luck diesel fleet mechanic 20 yrs.

black smoke means excess burning fuel. Look at injector pulse width. Special tool required. Sounds like to much fuel for sure. Also fuel has to atomize to burn. So if the injectors are clogged they do not spray mist they spray streams that do not burn correctly. This could also cause excess fuel in the cylinders thus the black smoke. If your truck only does this upon first start it could be the glowplugs. They are not heating up enough to burn the fuel when your engine is not to operating tempature. If it smokes black smoke constantly then the fuel system does need to be fixed.

Easiest is to look at air filter, black smoke is running to rich, change your fuel filter & run a tank full of Howe's, you may have to take truck in and get injestors looked at

Air Filter 1st, then most likely an injector problem or the cam

sensor are common...

the chevy ang guy is right you have a problem with the fuel system, most likley one of the injectors is bad and is just dumping fuel inside the chamber.

try changing the fuel filter and make sure teh exhaust is not plugged up with soot. They can burn the soot out if it is built up.

check the diesel pump

Change the air filter first.

smoke from the exhaust would indicate a blown gasket somewhere...from the engine compartment ...burning oil...if your loosing power then i assume its from the tail pipe that your smoking cuz you got a blown head gasket or possible valve cover gasket...just a guesstimate...gl...