my fuel pump stays on after i shut the engine off for about 5, 6, seconds anybody has an idea why?

 

If I had all your vehicle info, or even some vehicle info I could look for bulletins.

 

my guess is its filling the lines with gas pressure so when you go to start it the next time it wont crank for a second both of my blazers do it and my pickup do im pretty sure its what there supposed to do..

 

is that the small like humming/buzzing sound you hear that sounds like and accuator or small motor?

 

if you talking to me yes as soon as you turn off the truck the pump will run for a sec to fill the lines or prime it as some would say. if it didnt the next time you go to start it it wouild crank over until it had enough psi of fuel to start which is around 56-60psi.. but if you were not talking to me then mybad...lol

 

*Moving to 2nd Gen Tech*

Why would lines that are already full and pressurized need to prime??? The fuel pump is always supplying more fuel than the engine requires. The fuel pressure regulator maintains proper fuel pressure in the line while excess flow is diverted back to the tank.

The OP has a '96 Blazer.

 

I was just doing some reading through the '98 manual ( I don't have the info for '96), and it says that the VCM powers up the fuel pump for 2 sec when the key is turned off. Why.... I don't know.

Circuit Description
When you turn ON the ignition switch, the Vehicle Control Module (VCM) turns ON the in-tank fuel pump. The pump remains ON as long as the engine is cranking or running and the VCM is receiving reference pulses. If there are no reference pulses, the VCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops.

The VCM will also turn ON the fuel pump for 2 seconds when the ignition is turned to the OFF position.

An electric fuel pump pumps the fuel through an in-line filter to the Central SFI unit. The pump is attached to the fuel level meter assembly inside of the fuel tank. The pump is designed to provide fuel pressure above what is needed by the fuel injectors. The pressure regulator keeps the fuel available to the injectors at a regulated pressure. Unused fuel is returned to the fuel tank by the fuel return pipe.