Why are there so many opinions on what the minimum fuel pressure to the VP44 should be??? Can't find the post now with the sheet that show's fp should never be below 10psi??
https://www.dieseltruckresource.com/...d.php?t=204013 Found it

 

Cummins says 7 or 8psi.

 

Cummins recomends a volume test.

 

What happens if you give it more pressure...like 15?

Pressure is restricted volume, so if you got the pressure, volume is not a problem. So says my high school science teacher...and I passed his class

 

Volume and pressure are two very diffrent things.

Just like amps and volts.

 

Everyone has a different opinion on the subject, but like mentioned above "pressure is restricted volume", or a measure of restriction. Positive pressure means there is some restriction, and as long as you have positive pressure you have sufficient fuel for the truck injection pump IMHO.

 

They are also related. You can't have flow without pressure, you can't have pressure without flow (in a dynamic system).

 

This is from my service manual:


SPECIFICATIONS
FUEL SYSTEM PRESSURES—DIESEL ENGINES
DESCRIPTION PRESSURE
Fuel Transfer (Lift) Pump Pressure With Engine
Running
Minimum 69 kPa (10 psi)
Fuel Transfer (Lift) Pump Pressure With Engine
Cranking
Minimum 48 kPa (7 psi)
Fuel Injector “Pop Off” Pressure 31,026 kPa (310 bars) or (4500 psi 6 250 psi)
Fuel Injector Leak-Down Pressure Approximately 20 bars (291 psi) lower than pop
pressure
Fuel Pressure Drop Across Fuel Filter Test Ports 34 kPa max. (5 psi. max.) at 2500 rpm (rated rpm)
Overflow Valve Release Pressure 97 kPa max. (14 psi.) at 2500 rpm (rated rpm)