Help with fuel pressure

[Luv2ridexl]

I have a 2000 Ford ranger I need to test the feel pressure...Truck's not running so we realized that the key had been left on the battery was dead on the truck.... Will it give a correct reading with low truck battery? Sounds like a sample question huh? Just charge the battery duh... Problem is I wasn't there they tested the fuel pressure anyway and took the gauge back with them and its no longer available to me

 

[scotts90ranger]

As long as the voltage is high enough to operate the fuel pump to the regulator setpoint then the voltage doesn't really matter, not sure I'd trust it though unless it was showing the correct pressure...

 

[Luv2ridexl]

As long as the voltage is high enough to operate the fuel pump to the regulator setpoint then the voltage doesn't really matter, not sure I'd trust it though unless it was showing the correct pressure...

Thank you for replying