Weird problem

[vettman]

I have a 03 6 liter that I have changed to ARP studs, EGR delete Kit, Electric Cooling fans and Hypertech ECU upgrade. The engine ran very strong until the other day when it began to run rough and smoking very heavely. It was dark so I couldn't see the color of the smoke. It still ran strong until I get to a light and then its running rough again. The next moring I wa going to read the codes but none where logged. I tried to start the engine to see if it was still running rough. The engine started to rotate and then locked up. It was a soft lock up, not metal on metal. I was thinking it might be fluid, water or fuel in one of the cylinders causing the engine to lock. Looking for ideas or thoughts as to what this could be.

[hack'n'bash]

most likely cause is a failed injector, if you have no codes indicating which cylinder it is, star by removing the glow plugs one at a time,start with the easiest obviously, try to crank it over, when you get to the hole that is full of fluid it'll pump it out, there you go. It should be fuel, since you have no egr cooler. now change that injector. If you pull all the glow plugs and it still doesn't crank you got bigger problems, pretty unlikely though with the symptom you provided.