My 2004 Duramax has been losing prime. The first time I pumped it up after it died I did not know about the bleeder and pumped it up and it ran fine for a long time. Now I have a error code that indicates I need to replace the fuel pressure regulator (FPR) which I have purchased but have yet to put on. My truck is now losing prime again and when I pump it up fuel leaks from somewhere under the hand pump.
Is their a new problem or was it this new problem all along and not the FPR?

 

before tearing into the valley of the engine i would put one of these seal kits on the filter housing first: duramax primer | eBay

it can also be one of the filter O rings. new filter will come with a new set of O rings. the other place to check is the water-in-filter sensor. this is made of plastic and have been known to crack and leak.

the last place is the filter housing itself. the casting can develop a hairline crack and leak and loose prime.

on the hose coming out of the filter, replace it with a clear piece of tubing and check for air bubbles while the engine is running. this will help determine if you fixed all of the leaks

after you make sure you are not loosing prime, clear any of the codes, then drive it around and see if you are still having FCA issues

Good luck

 

Mine did this rolling down I-75 with 18000 behind me. I found that the fuel filter had spun off a bit plus the three torx screws around the primer pump had backed out. I tightned the filter and screws 10,000 miles later and no problems.