bubbling injector

[morgan1227]

So I'm bringing back to life an '85 740, almost there. I have been able to get it started (lots of priming & bleeding). It runs rough/noisy, so I have been bleeding again. When cracked open, all injectors spray fuel (and I mean spray) except the injector farthest to the back (cyl 6?). It foams white and just burbles out. I ran the car for 5-10 minutes tonight bleeding it this way, plus drove around the block a few times, real noisy on acceleration. Shop-Rebuilt motor and new IP.

Here come the questions: Bad injector? Dirty? Should I inspect and clean before buying another? Do I just buy a nozzle, or the whole injector? thanks, Bill in AZ