The Pinto fuel system is pretty simple and straightforwar d. Not much that can go wrong with it that would be hard to find. If a new stock oem fuel pump is not pumping, and there is gas in the tank, then there is something plugged up farther back, or there is an air leak in the line between the pump and the tank. Try pumping gas from a gas can with the stock pump and a hose between the pump and gas can. The pump is self priming, and if it doesn't work, either the pump is defective, or possibly the pump arm is bent, The pushrod is worn, or the cam on the auxiliary shaft is worn down. What engine do you have, the 1600cc or the 2000cc? If the fuel line to the gas tank is plugged, compressed air might clean it out. Otherwise you would have to remove the sending unit assembly. I have not had this problem so far with the Pinto, but I have had a lot of damage done to motorcycle fuel systems due to ethanol gas. It melts rubber and plastic, corrodes aluminum and rusts iron and steel. Bad stuff.