I have a 81 240d. I was about to replace my injectors because of rough idle and low power. I started the car before I started the repair and it ran rough. It usually does. I disconnected the fuel line to one injector and found I had no socket that fit the injector. so I reconnected the line and the return hose, thinking I would find the correct socket and continue. I immediately tried to start it again. Wouldn't start. Disconnecting and reconnecting the fuel line was all I did. I checked and fuel is getting to the injectors. Cranked and used glow plugs. Won't start. What did I do?

 

air in line?

 

Deisels are finicky with fuel lines, and it likely needs to be purged of air. If you have a service manual, there should be a procedure for how to do this. Or maybe a YT video.