I have been working on my 1983 240D for a few years, every time I started it after doing work, such as replacing fuel return lines, replacing the fuel tank screen, and cleaning the fuel tank, there was no problem starting up, as it would start in about 2 seconds no matter what was done or how long the car sat. (see video 1 Url:
https://www.youtube.com/shorts/KPaEEZYF7dA )
now after changing the fuel filter(attached picture), it barely starts, if at all, coughing up black smoke from the exhaust. (video 2 url:
https://www.youtube.com/shorts/youG3Uja27A)
Any ideas as to what the issue is?
Thanks for the help.