Does the fuel pump on 5th gen turn on and prime for several seconds to build up the pressure, or it doesn't? I have read various opinions on older models of 4runners and Tacomas.

Looking at the electrical diagram, once the EFI relay and C/OPN relay are activated, it should get power even before the car is cranking.

I check mine yesterday and the pressure was 0 with the key in the ON position. I also put the ear next to the fuel tank when the key was in the ON position, and the pump was not running. It runs and build up pressure around 50psi when the engine is running, or cranking.



According to the repair manual (page 2469), you have to use Techstream to check the pressure with the key in the ON position.