hi,
I have a 1984 240 diesel with 200000Km. It has a leak from one of the
fuel lines leading into the fuel injectors. When I start the car I see fuel
misting out from the top of the fuel injectors. It's fairly wet and I can
smell the fuel. Can someone help with this problem? Could it be a DIY job?
Any advice is appreciated.

Is one of the injector pipes leaking? Occasionally they get little pinholes in them. The best solution is to replace the whole pipe, but if you're in a tight spot, you can sometimes solder it back together with decent success.

If fuel is coming from all of the injectors, there is another problem like a blocked return, loose fittings, loose return hoses, etc.
--
1992 940 wagon, 77k
as well as others.

first off thanks for the replies. I'm going to clean up some of the mess,
let it dry out and try to pinpoint the leak. I imagine it will be alright
to loosen the top nut and tighten it again. I'll let you know what happens.
thanks.

Is it commong from the pressure or the rubber return line?
If rubber, replace, if metal pressure line , loosen the fitting and take some tension off of the line while retightening it. try that a few times until you can get it to re-seat

Those things don't usualy leak for no reason, check to make sure your fuel pump hasn't vibrated loose.