I have an 89 Iroc with the 305 TBI. It was fine until I pulled the air filter housing and then the pump started running. It runs so much that I can hear it going thru the throttle body and back out the return line. It wont stop unless I unplug the battery. I pulled both fuses for the fuel pump and it keeps going. HELP

 

Bad Oil Pressure Sending Unit (OPSU). The OPSU runs the pump when it 'sees' oil pressure - it can go bad in such a way that it 'thinks' it sees oil pressure when there is none. The OPSU has a direct uninterrupted connection to the battery, and a direct uninterrupted connection to the fuel pump. There is a fuse, tucked in the fenderwell behind the battery in a weatherpack - it will have one orange and one red wire running into it - you can remove that fuse and reconnect the battery - as long as the fuse is out the pump will not run. Put the fuse back in to make the pump run again. This will get you by without disconnecting the battery until you can get the OPSU replaced - just take the fuse out after driving and replace to drive again. The OPSU should be above the oil filter, about $35 to replace. It will have a 3 wire connector, one red wire, one orange wire, one other color (the other color is for the oil pressure guage, the red and orange are power in from battery and power out to the fuel pump.