Actually straight out of Dodge's FSM is 10 PSI minimum...



You can download the FSM books here...
www.pdftown.com

 

The pressures noted are for the purpose of lift pump diagnosis.

I can't count the number of times I have been told that high inlet pressures are rupturing seals, blowing out the pump, causing extra wear, even costing horsepower.

After 60,000+ trouble free miles with no less than 37 PSI EVER and 45-46 at idle, I have to lose economy, power or have to replace a pump. I haven't even thrown a code. And since I had been told about the negative effects, we replaced the cam in a bone stock '02 and ran it exactly the same way. Only 84K on that pump....TROUBLE FREE.

It's not that anyone is wrong, but there is clearly more than one way to do things and the hearsay from Cummins, Bosch or whomever appears to be second, third or more hand.

I am still looking for one of these blown out seals. But if I only get 100K out of this pump, I'll be satisfied.

Just for the purpose of info regarding the overflow. I still get 35 psi WOT box on kill with 200+ HP injectors with NO OVERFLOW INSTALLED! This is with a straight fitting. Makes starting near impossible, but it does work and maintain pressure. I would not run it long term this way as it is not good to not have the back pressure on the system. The truth is, there are far more restrictions on the front of the pump than some would expect.

As far as starting issues, this is an electric pump thing. I don't start making pressure until the engine begins to spin. So I am started long before it's at 20psi and when it kicks over, I go to 45 psi instantly.

I have built a bypass regulator but chose to not install it as I would have so many problems in the current configuration. At least I wanted to see if I was going to have issues. Not one yet.

Dave

 

Wow! 37-46 PSI of fuel pressure...

Dang I thought for sure is would blow out a seal or rip the diaphram inside... But made this far without problems. I wonder how many others can follow this path without blowing up a pump os such?

Me... I've been keeping it between 10-20 PSI and I've got 86K miles on my pump and still going strong. Like you said if the pump died at 100K miles... So be it...

 

mines beeng running over 214k with a fass 150 installed at 60k producing 16psi wide open throttle with my 150s and the juice

 

Hmmmm....thats interesting with that high of pressure....well if it works and is still working so be it!...

 

agreed good luck man