ive replaced both fuel pumps and sending units but when i put the rear tank on it creats high pressure in front tank and pushes fuel out of fuel neck,but put the front tank on and everything is alright,any ideas what the problem can be.
The only thing it could be is the check valve that is part of the fuel pump/sender unit assembly on your forward tank. It's not servicable separate from the rest of the assy. It's possible the one you got was bad off the shelf.
