1988 chevy Silverado

[moparmaniacs]

Just put a new engine in my truck runs great when hooked up to obd computer but when you disconnect the the obd it dies fuel pump stops pumping any ideas why?

[carriedi]

you should check the power coming out of your fuel pump relay. Should be a pink and black wire. then check power on the tan and white wire that goes to the fuel pump back at the tank or wire harness along the frame. According to the wiring diagram there is a 20A inline fuse between the pink and black wire and the tan and white wire. If you don't get power on the pink and black wires out of the relay try switching the relay out. (it should give you a two second prime when you cycle the key to the run position) start with that and let me know what you find out.

[Guest]

Do u have a 350 engine or a 305 engine? ?
Have not seen no one ask u this.. but it does make a difference. .
Thanks..