Crank no start?

1993 FORD F-150
168,000 MILES • 5.0L • V8 • 2WD • AUTOMATIC
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PARDUE1360
  • MEMBER
  • 1 POST
Fuel pump relay not closing, both pumps run when connected to battery 12vdc, spray fuel into engine and it'll run, with pump straight wired and correct fuel pressure still we not start.
Dec 18, 2022 at 12:23 AM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Hi,

First, switch the PCM power relay with a different one having the same part number to see if it makes a difference.

If there isn't a relay with the same part number, here is a link that explains how to test one:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

I also attached the schematic for the fuel pump. If the relay won't actuate by itself, either we have no power from the power relay or there is no ground path via the PCM. We will need to check that.

Let me know what you find.

Joe

See pics below.
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Dec 18, 2022 at 12:15 PM
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