No power to the fuel injectors on 1990 GMC 1500 Pickup

No power to fuel injectors, have replaced module, brain box,fuel pump, and not sure what else to do

Asked by for the 1990 GMC 1500 Pickup
You will need a wiring diagram and trouble shooting flow chart to figure out whats wrong. Autozone have some popular workshop manuals for free on line once you register (for free) on their website
and get an online repair manual subscription.
There are two companies 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 and much cheaper than the factory manual try Alldata which is very easy to navigate or Mitchell on line and get an online repair manual subscription. I prefer Alldata its got more information and is easier to navigate.
Thank you very much, I will check out the manuals