in older cars like a model a Ford,
the carborator was gravity fed so perhaps .5 psi or zero uphill with a low tank
carborators and a fuel pump 5 psi is plenty to lift the gasoline 10 ' or so
with fuel injection about 100 psi is common
diesel can be about 1000psi fuel injected at TDC
The fuel pump pressure may vary by vehicle. However, on average the fuel pump pressure with the engine running should be between 4-6 psig.
While engine is running remove the fuel pump fuse. Engine will run out of fuel when pressure drops.
The fuel pressure for a 1994 Chevrolet Z28 with the LT1 engine typically ranges from 43 to 47 psi (pounds per square inch) when the fuel pump is running and the engine is off. When the engine is running, the pressure should remain within this range. It's essential to check this pressure with a fuel pressure gauge to ensure proper engine performance and fuel delivery.
In most vehicles you can remove the fuel pump fuse or fuel pump relay as the engine is running, the engine will stall when the pressure is gone.
If the engine is not running the pressure should be 35 to 40 psi. If the engine is running the pressure should be 30 to 45 psi.
Fuel pressure (ignition key turned to on, engine not running): 50 to 60 psi
If engine is running then the answer is yes. And pressure will stay in the fuel line for some time after you shut the engine.
With the engine running, remove the fuse or the relay for the fuel pump. The engine will stall soon and the fuel line won't have any pressure left.
Remove the fuel pump fuse or relay while the engine is running. It will relieve most of the pressure once the engine has stalled.
you need at least 50 psi to run and 55 or so to keep it running thats with cpi engine the others use less pressure and a different fuel pump....
Approximately 30
50 to 85 psi engine not running. 25 to 35 psi engine running.