Engine/Transmission (1998.5 - 2002) Fass losing psi

[LBello]

i installed fass 150 just the pump. Psi was around 18-20 psi then just started losing pressure very slowly. It took months. Now it is at 14 idle 11 wot. I thought it was the filter but readings is the same. I have an isolater pressure gauge, dont know how or if i do need to bleed it. I believe i had maybe 7000 miles on this filter.

 

[NDaniels]

I'd try to add antifreeze to isolator, just pour it in the guage side. You should't have to bleed it unless its a long way to your guage (I've never bled mine). I did have a leak once at my guage, noticed my fuel psi slowly drop. Fixed leak and filled isolator been good ever since.

 

[Cummins724]

I have the same pump & noticed a change in pressure. It used to read 16. 5 psi. idle 12 psi wot. Now I am getting 22 psi idle 5 psi wot. I have noticed air bubbles in the clear tubing near the gauge. I haven't got around to bleeding it yet.