what supplies the injector pump in my truck with fuel pressure? i was in the tank a little while ago and there's nothing there, just the filter and sender as far as i could see. is it inline somewhere and is there a way to adjust the output pressure of it?

 

There is lift pump on the block. It is run off the cam, and is located down and rear of the fuel filter housing.

 

it should have a mechanical fuel pump on the side of the block, check right below the fuel filter.

 

Fuel supply pressure is regulated by what's called a overflow valve on the return line where it leaves the injection pump.
Increasing the pressure above Cummins specs will gain you nothing and pressure in excess of 45 psi can cause expensive pump damage.
More is definitely not better.
Pressure below spec will cause performance problems.
A FP gauge is cheap and easy> http://www.cumminsforum.com/forum/94...-12-valve.html

 

I see. so if i get this right, as long as the psi is there, and the amount of fuel going out of the pump does not exceed the amount coming in, then leave the lift pump alone right? these lift pumps didnt have any reliability issues if i remember correctly, and they're good for a fair amount of mods before they need upgrading right? yes im getting a fuel pessure gauge to replace the tranny temp gauge on the triple pod

 

That would be sort of impossible right?
More fuel should flow though the return line back to the tank than goes to the injectors though.
Excess flow cools and lubes the injection pump.

The stock mechanical lift pump is very reliable.
My 2500's pump was replaced at 225k miles.
The 3500 has 275k on the original pump.

Well proven that the stock pump and fuel delivery system can easily support 600 hp.