Lift Pump Pressure

[six_sloww]

Looking for some help understanding the low pressure fuel system on a dodge, I'm using a 6.7 cummins pump as a dual fueler on my 6.7 ford and I'm trying to get to the bottom of an issue.

The cp3 is on a completely standalone low pressure circuit; I have a sump feeding a fuelab velocity 200 lift pump (for a dodge) and 1/2 inch line feeding the inlet, and 3/8" line on the return side going through a fuel cooler then returning to the tank.

It is my understanding that regulating the return side on the cp3 is a no-no, so I've avoided that by just letting the fuelab feed at the preset 18psi.

Trouble is on a long drive my 5psi low fuel pressure warning light comes on, I know a cp3 does not require high pressure but I don't feel like cruising along at 2000 rpm should be able to pull the lift pump down that far? The fuelab is on low speed and it is somewhere in the low 100gph at that speed which still should be more than enough shouldn't It? If I click it on high speed the light never comes on.

On a dodge when an aftermarket lift pump is installed is there still a regulator somewhere besides at the lift pump?

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[six_sloww]

Turns out I have a duramax regulator on my fuelab, only feeds 8psi koeo.

Is there a reason why the cummins pumps cp3 are usually fed more like 18psi?

Fuelab already offered to ship me a new spring and I'm going to take them up on their offer, just curious.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[Pvmt-Pndr]

I only know what I've read. I believe you're talking about the FCA. Most guys swap out the duramax FCA for the Cummins because the duramax is a lot more picky about everything.