My wifes S-10 Blazer quit at the bottom of the drive way and won't restart unless we pour fuel into the TBI body. Put in new fuel filter but still no start. we can hear the fuel pump humming and when we checked it we got about a 1/4 cup of fuel at the line in back of the fuel filter. I put on a donor fuel pump from a 1978 vehicle with an electric pump but it still won't draw any fuel up.
Is there a valve in the fuel pump that won't let my donor pump work if the in vehicle one is junk? is the fuel pump located in the tank or on top of it? I even tried to put about 7 psi back thru the line to see if maybe the strainer was plugged but I couldn't hear any air escaping into the tank. the vehicle is a 4x4, 4 door and as it says in the title it has the 4.3 V/6 with TBI and 133,000 miles on odometer.
thanks for any help anyone can give me.

 

If that pump was used in a carb application, it may not be a high enough pressure output. A TBI motor requires 8-10psi while a carb can get by with much lower pressure. Also, a lot of the in line pumps used for carb applications do not deal too well with restriction in the suction side of the pump. If your stock pump isn't putting out enough pressure, adding another pump that has an even lower output isn't going to help matters.

It sure sounds like the pump in the tank is bad. Good news for you is that the pump itself isn't too expensive.

And, it takes 3 drive axles to be a 6x6. This is a 6x6: