Check your GPR, if it's ok then it's probably glow plugs...
Agreed. The white smoke makes me think so.
Originally Posted by 7.3powerstroke2000
I've been thinking about that. how do you check it? multi-meter?
GPR: 1) If it's drawing current, you'll see the volt meter on the dash dive to left after you turn the key on. 2) You can by-pass it by jumping the terminals. If you bi-pass it and it starts right up, you have a gpr problem. Careful doing this though, you'll be throwing sparks if you try it.
If it does test out to be the gpr, look into the Stancor 586. It's a better replacement.
Oh, thanks to Superduty4x4 for this post on testing gp's:
You can ohm check the GP's without pulling the valve covers. The connectors are arranged as such:
G = glow plug
I = injector
C = injector common ground
To test the glow plug measure ohms between each G pin and a good ground. Should be between 0.2 and 2 ohms. Open (no resistance, 0 ohms) means a bad glow plug. Just touch the pins inside the valve cover connection with the lead on your multimeter.