I have a 1985 300CDT. Odo wasn't working when I acquired it but it probably has 250,000 km.

I was having issues with it last winter before it went in to storage, it seemed to be a fuel starvation/air issue after it sat for a few hours. It would start, run for about 1 km then die. I would eventually be able to get it going again and it would run fine after that.

I parked the car for the Canadian winter and rebuilt the injectors with monark nozzles, changed all the filters, in tank screen and new glow plugs as well. It was running well but now it is blowing incredible amounts of black smoke, mostly on harder acceleration and at idle. It stinks big time. It has always smoked a little since I got the car but it is so much worse than before. Also the trans doesn't seem to downshift properly. If I don't manual downshift or come to a complete stop it doesn't downshift and accelerates like a snail.

I have the car on WVO/Diesel, this is by no means my first MB or WVO kit though. But interestingly, I have a fuel pressure/vacuum gauge to monitor the pressure of whichever fuel I am on. I measure the pressure before the lift pump and I have electric fuel pumps separately at the VO and diesel tank. I have good vacuum in the lines and no apparent leaks when under pressure....everything seems ok.

Any ideas on where to start?

My best guess is:

1. I botched the injector rebuild
2. The engine is worn out
3. My trans or vacuum system is not shifting properly

Should I try new injectors or is there a bigger problem?