Originally Posted by rla2005

Many aftermarket pumps do not have the built-in high pressure check valve or it did not get installed when it was manufactured. More than a few times someone has found the latter on their new pump. The tank that is getting filled when not selected has a bad valve. Could be the high pressure check valve or the shuttle valve. If the latter you have to replace the entire Fuel Delivery Module (FDM).

Originally Posted by Davis2

Is there anyone who has the best system for this setup?