Fuel pump problem in caprice LS 1990

Tanx, but when I put the key in on position the pump doesn't work even for 1 sec. And the pump wires doesn't show any voltage. After I start for 3 times and more gas comes to the back of injectors and before that there is no gas in fuel line from pump to injectors. I also test to put the key in on position 2 or 3 times before start the car but it doesn't help , as I notice no voltage comes to pump in on position.

You got a tricky one that's for sure...

I didn't get you, what do you mean? My English isn't very good and I don't understand what you mean. Please explain how can I fix it or which part should I change with new one.