What is my pump doing now????

[Extended Power]

Everytime I go to start my truck, I turn the ignition key to "ON", wait for the glow plugs, and then start the engine.
While the key is in the "ON" position, the fuel pressure jumps past 60 psi, to almost 75 psi. Then, when the truck starts, it resets to zero, then jumps past 60 psi again.
This morning, with the truck already running, the pressure climbed to 100 psi, before it settled down to 65 psi.

When the truck is warm, the pressure is at 60 psi all the time, with fuel returning to the tank. (I can hear it in the fill spout)
When I say climbs to 100 psi, I mean, climbs, not jumps.

I can not hear any fuel returning when the pressure is above the 60-65 psi "Setpoint" of the FASS itself, but as soon as the pressure falls back from 75-100 psi, it is returning fuel.

What's up???:bang

 

[Diesel-Dan]

Everytime I go to start my truck, I turn the ignition key to "ON", wait for the glow plugs, and then start the engine.
While the key is in the "ON" position, the fuel pressure jumps past 60 psi, to almost 75 psi. Then, when the truck starts, it resets to zero, then jumps past 60 psi again.
This morning, with the truck already running, the pressure climbed to 100 psi, before it settled down to 65 psi.

When the truck is warm, the pressure is at 60 psi all the time, with fuel returning to the tank. (I can hear it in the fill spout)
When I say climbs to 100 psi, I mean, climbs, not jumps.

I can not hear any fuel returning when the pressure is above the 60-65 psi "Setpoint" of the FASS itself, but as soon as the pressure falls back from 75-100 psi, it is returning fuel.

What's up???:bang

Sometimes with the higher pressure springs, they cause the ball to stick due to they are pushing harder than the standard 15 PSI springs. I dont see this causing an issue as long as the pressure comes back down to normal levels as the PSD can handle the pressure with the way its setup. I dont see any damage with our pump as the high pressure releif will kick in and protect the motor from high amperage....

 

[Extended Power]

Cool, Thanks Dan.

Like I said...after a while, it does drop back down to 60 Psi...I was just kinda concerned about the initial high pressure blowing an o-ring off an injector or something.