I have a 90 fullsize blazer I need to remove my gas tank and need to get all the gas out. I tryed siphoning but I couldnt get the hose down all the way is there a way I can hot wire my pump? like using the diagnostic port under the dash ? so I can just pull the hose and let it pump into a gas can also since I will be having my tank out I want to replace the fuel pump, what is the best and most reliable brand ? also is it worth replacing the sending unit ?