Dodge 2500, 2001, 24v turbo.
I have a FASS
system and recently the pressure would be ok at startup and in park, but when I drive the pressure drops down to 5 psi or below and then starts to climb back up to between 10/14 psi. Under hard throttle the pressure drops then climbs back to around 10 psi when the demand is taken off the engine.
What I've tried: Took the tank off and cleaned it and the in-tank filter screen. Changed the FASS
filter. Checked the return valve in the FASS
pump body to make sure it wasn't stuck open. Bled the isolator under the hood for the pressure guage.
The pressure, when I first installed the FASS
system, used to come up to 15 psi when I turned on the key to wait for the "wait to start" light to go out and the pressure would drop slowly , but now it goes to 15 psi and drops immediately.
Could the diaphram in the VP44 be bad and if so, is it an owner replaceable item? I've heard that there is a thicker diaphram available, but my local Dodge dealer won't even discuss it, unless I take the truck to them.