Vortec 7400 hard to start when cold

[Falcon_LS]

The truck's a '97 GMC Suburban C2500 with the 7.4L Vortec. Since the weather cooled down and the engine cools down much more, the engine is harder to start when cold. If it's been sitting for a couple of hours, it cranks for a good couple of seconds before it finally starts and puffs out black smoke out the tailpipe for the first three or so seconds. It's faint black smoke at first, then it turns into a cloud and goes away.

First thing that came to mind is the fuel pressure regulator, although I have yet to check it (going to check fuel pressure as well). Just wondering if there's anything else I should check? Thanks!

 

[Boomer]

Leaky injectors??

 

[The_Jeff]

I 2nd the leaky injector theory. If your FPR were bad it'd be blowing lots of smoke and only run good under WOT.

However it should be easy enough to check its vacuum line for gas. Throw a scanner on it to check out all the sensor values while at it.

 

[daman]

Can tell you right now its fuel injectors! these 7.4's came from the factory with bad injectors,they leaked dripped fuel once shut down,change them out along with your fuel regulator and all will be good.

i own one(1999 k3500 7.4) Ive been all through this ordeal,google it you'll see.