Rail pressure building at idle

[Pistol_91]

Is this normal? The longer I sit and idle the more and more the pressure builds up, I know once I drive it, it will go back down but I noticed this while I was dialing in my idle. I revved it a few times slowly to see if it would change but it didn't. Any ideas?
idle log with revs.hpl

[engineermike]

It’s normal. The fuel in the rails has nowhere to go if the di injectors are off so thermal expansion causes the pressure to increase. It actually does a pressure relief/maintenance cycle (di injectors fire a few times) when it gets over a setpoint.

[Pistol_91]

I have never paid any attention to it like this at idle. Probably why I've never noticed it. Makes sense though. Thanks mike

[veeefour]

Theres is a setting under fuel tab called heat soak

[Pistol_91]

I was looking for a tab last night. I'll check it out. Thanks

[engineermike]

There are parameters as follows:

"Max allowed FRP before forcing DI FRP Maintenance" set to 3963 psi in the cal I'm looking at.
"Percent above FRP Desired for lower limit of DI FRP Maintenance (Disable Below)" set to 100%.
"Max Percent DI to enable DI FRP Maintenance" set to 80%.

I interpret this to mean if the FRP exceeds the desired FRP by double, but not more than 3963 psi, then it blends 80% DI.