how to troubleshoot the fuel pump on 1990 GMC 1500 Pickup

replaced the engine and no gas is getting to the thottlebody

Asked by for the 1990 GMC 1500 Pickup
There are 4 engine options this year each has slight differences in the wiring diagrams. They need an input from the oil pressure switch to turn on the fuel pump relay. The wiring diagram is easy to follow. There is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subscription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try and get an online repair manual subscription.