GMC S15

I have a 1986 gmc s15 pickup 4 wheel drive. The fuel pump if I straight wire it to the battery will come on but if I turn on the key it will not come on. I checked the fuel pump power wire under the hood and no power is in the wire even when I turn the motor over also the fuel sprayers has power going to them also but they will not open when I straight wire the fuel pump. If I take one of the wires from the sprayer and touch it to the neg. Side of the battery the sprayer will open but none of it works with the key turned on. Only the sprayer has power going to them but will not open.