Please help me! I have a 1987 300D Turbo which I recently installed a "good" used OM603 motor into. The original motor seized up due to a failed oil pump. The engine swap went fairly well and the car fired right up after everything was connected! I was so elated... the 6-cylinder diesel sounded so good and would idle at approx 600 RPM. You could hear the turbo whirring and everything seemed fine. I decided to take the car for a test drive. I immediately noticed that the car was quickly loosing power and I couldn't get above 30mph. I began noticing some whitish smoke behind the car and I thought I had better head home. I went to back off of the throttle and it died. I cranked and cranked and it finally restarted but had almost no power. I finally made it back home and the car would idle very well but would die if I tried to rev it above idle speed. It would restart (for a few trys) if I cranked and cranked on it. Finally it decided it wasn't going to restart at all. I have checked the compression and it is in the 400 range and all 6 glow plugs are glowing red-hot. The injectors look pretty good and are MB reman units. What could be causing this no-start? It turns over and over and appears like I am getting fuel at the injectors but it will not fire. Also, I have noticed that after cranking for a few times, the cooling system seems to have pressure in it. I have cracked open the radiator cap a few times and it sure seemed to be pressurized. When the engine was running, it came up to operating temp just fine (approx 80 deg C) and all seemed well. Please help me...

Thanks.