I purchased the truck knowing it wouldn't run on it's own. It'll run if you pour gas in the throttle. It had no fuel pump when I got it. I just replaced the whole fuel sending assembly with one from MTS Company. When I turn the key to accessory, I hear the pump whine for a second or two, but when I turn the key, it'll sit there and crank. I unhooked the sending hose and put it into a container to see if it was even pumping out any fuel. It is not. How can my pump be priming but not pumping? Thanks in advance!