1990 Ford F-350 Q&A
1990 Ford F-350 Question: why aren't my injectors working?
With the key in run your fuel injector connector should have power on one wire and a ground supplied by the ECM (Engine Control Module) on the other wire while cranking. You need to determine if there is power present, if not then you need to check the power source for the injectors. If you are not getting the ground from the ECM while cranking then you could possibly have an issue with the crankshaft sensor that the PCM uses to "trigger" the injectors. You could also have a wiring issue, ECM issue, security system issue, or another sensor causing a problem. - LTS