High Rail Pressure at Idle

P

Penn6.7

New member
Just finished building a new engine. 6.7 running 04 electronics, 400% over Injectors, stock LBZ pump over a 12mm 6.7 pump using ATS Controller. Belt on running I'm at max rail, take belt off rail is at demand psi. Replaced pump, FCA and 3 ATS controllers. No improvement. I'm lost. Tested FCA circuit from the ECM and its fine, checked continuity and the wires are good. Certainly it can't be another controller but I have no idea at this point.
 
ATS has a reputation of what? I've got nothing bad to say about my ats controller. It does make the truck cough on startup for no apparent reason I will say.
 
How much lift pump pressure do you have? Does it do it when warm? Take the fuse off the lift pump and let it idle. I have a ppe kit my lift pump would make 18psi. My lbz pump would hate it. It would idle at 29k at the rail. But as soon as I take the fuse off the pump. It would go to normal idle pressure.
 
I went from a ppe to a fish controller it would do the same. I changed the fca from the dmax one to a cummins one didn't help. Until I lowered lift pump pressure to 12psi.
 
Sorry for the open ended response. The first pump I had was trashed, replaced the pump, new pump had a bad FCA out of the box which didn't help the troubleshooting process. Replaced FCA and most of the problems went away. Once pressure was under control it was found that the return to tank line was too small for the larger dual pumps. Return size increase and rail returned to normal pressure.
 
I am having a similar issue with mine but the rail pressure is 8-9k at idle.

replaced both fca's
replaced controller to a fish tuning.

i bought an aeromotive 230gph lift pump which recommended a -10an line into a fleece fuel filter bypass then -8an to each pump. I have a -6an return hose. The lift pump is set on the lowest setting (10psi) and at the engine it is reading 4psi (increasing causes the idle pressure to rise) I am thinking that FLOW and psi are not the same as the feed is 5/8". Do I need to add a aeromotive FPR on the return line?

At this point I am a little stumped and would appreciate any help/advice you can give.
 
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