1999 Cummins losing prime
 

When the truck turns off for more than 30 minutes I have to bump the starter and then crank it for about 5 seconds after that to get it to start. I have a Fass Totanium 95 GPH and new remann'd VP. Both were done about 6 month ago and I havnt touched them since and they never gave a problem so I dont think its them. I dont some work with my return line and taking my injectors off recently so I think its there. Ive tightened all the fittings on the return T-Fitting, tightened the banjo on rear of head, tighted my banjo going into my VP and all of my injectors and still does it. It also is NOT leaking so its hard to fond out where its pulling in air.

Still lost on this if anyone can help. I attempted to replace the overflow valve banjo on the VP as well as got 2 new of the OEM washers and stilllosing prime after 20 minutes or ao. Next im gunna try the banjo on the back and 2 new washers for that but if that doesnt work then im going to be completely lost and where to go mext if anyone can help at all.

drive truck 10-15 miles. Shut off and pop tank cap immediately to see if there's vacuum or pressure. I believe pressure means sealing washers on injectors and vacuum means o rings