im working on a truck for a freind he just bought a 97 3500 12v with 250,000 miles on it it had a miss when he buy it. he brung over and i found #6 delivery valve aint pumpin it has nothing coming out of it until i pick up rpms a little bit but its causing a fuel knock in #6 cyl also i changed filter out and the dipshit who he buy from never changed it could trash got in #6 dv? ive already put in 90hp injs i had layin around and knock got better but #6dv is gone. wondering if this has happend to anyone else and could the dv be cleaned or is it as simple as a o ring?

 

have you removed the DV and looked at it? make sure the DV is in the right way the owner could have put it in upsidedown

 

its in the right way its squirtin just not enough to supply inj

 

your sure the plunger is turning like it should? how did the holder look? is the o ring sealing?