Yo Carlos,
WELCOME!
Try a
Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19Post Code(s) here according to:KOEO & KOERA helper can assist you by counting the codes. Some use their smart phones to record them.BEWARE OF FAN, BELTS, PULLEYS, HOT HOSES, IGNITION HIGH TENSION WIRES, AND ENGINE COMPONENTSOr ask local mom and dad parts stores if they will test it for you. The majority of parts chain stores tests just OBDII vehicles now.Or purchase a coder reader such as;"Innova ODB-1 and we generally recommend getting the extension cord with it, so you can work the ignition key in the cab while watching/holding the reader. It will save the codes but knowing when to go through the cycles and ensuring you get it right the first time can save time and hassle, especially if you're working on it by yourself, as most of us do." by BikerPepe`
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Is starter cranking engine over well?
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If no codes, Troubleshoot a No Start Ford 4.9, 5.0, 5.8) @
https://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-troubleshoot-a-no-start-1
Have a spark tester & fuel pressure gauge ready to test; available at most parts stores for a refundable security deposit.
Here is the 1990 F Series/Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manual (EVTM), Partial by member Kingfish999 in Google Drive (
similar to your 91) @
https://drive.google.com/drive/mobil...XB6NW5neFRoZGcSlow scrolling for my slow Comcast Highest Cost Blast Internet..Find page # of item desired in contents, then flip screen flip down like spinning a bearing then stopping periodically to see what page you are on.Suggest you download the docs for faster scrolling and to use the page index.