D6 9U Fuel injection leaks

Should not be exceptionally tight.....check the sealing ferrules for cracks....pretty common problem.

I have had a few where the end of the line was crushed a bit by the nut being tightened too tight I guess, and would never seal properly again. Look over the end of the line carefully and see if it has a groove pressed into it etc. One was totally deformed, it seems to not have been properly seated into the female piece before the nut was tightened.

What are the sealing ferrules? Is that the part that I am cranking down on? Or is it the part under the line? I checked all the ends of the lines and the other part it goes into before I put them back on and they looked good. I used all new o rings. Maybe I messed it up when I initially cranked it down. I'll have to take it apart and look at it. When it's not leaking it sure runs nice.
Thanks

That cone shaped piece on the end of the line is a hardened ferrule that seats against the injector body. They are not normally replaceable and would require a replacement line. Check them closely with the nut pulled back. If they are cracked, they will leak irregardless of how tight the nut is.

As OM said take the nut off the pump and see if the ferrule (tapered end piece)is cracked and at the dealer I have seen (found) lots of them cracked down across them and the only option is to replace the line.Normally as was mentioned they don,t have to be so tight to break your arm doing it for it not to leak.

I'll go out there and pull off the nut, see if it's cracked.
Thanks

Make sure you haven't cross-threaded the retaining nut for the injector lines. It's not hard to do, and this will result in fuel leaks if it happens .. because the cone section on the end of the injector line won't sit down properly on the injector, if the nut is cross-threaded.