Kerley

98.5 Dodge/Cummins 24Valve Complete Stock except for Big Air Cleaner and Fass DDRP, Fuel System Questions, The VP44 was replaced ten years ago but only has been driven 7K miles. Last week I was pulling my fifth wheel, moving some Cattle. My average FP is 17 to 20 PSI, on the way home I noticed the FP dropped to 7 PSI, I was about three miles from home so I continued at a slower speed, I did not want to damage the VP44. My FP, Boost, and EGT is all Autometer Electric. I installed a new Fuel Filter and my FPG was fluctuating between 5 PSI and 25 PSI, I am assuming there is air in the Fuel System, but worried that it is something else. I would like to install a Big Line 1/2" Fuel Kit, but I would like to keep my OEM Fuel Filter Canister. Would the OEM Fuel Canister, with the FASS-DDRP accept JIC 1/2" fittings?

AlpineRAM

If it was my truck... I'd simply replace the stock fuel lines from the tank to the filter with good rubber hoses, you need 10mm ID for the feed line and 8mm ID for the return. (About 2-3 yards of each, and 4 hose clamps.)
I've seen a lot of corroded stock fuel lines.

Disclaimer: I don't know what the FASS changes, but if you still have the stock quick connect fittings on the tank this sounds like a trouble prone area to me.

Kerley

Thank you, AlpineRam,
Have you ever replaced the quick connection from the fuel line to the fuel tank module? I'm thinking you may be onto something.

AlpineRAM

I replaced this on all the older trucks. The main problem was corrosion of the pipes outside of the tank, and that the quick-connects would not re-seal after being removed.
Another point of air entry is the flexible part of the fuel line, right where it bends upwards at the firewall.