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12 volts direct to fuel pump relay plug,no fuel pump hum

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12 volts direct to fuel pump relay plug,no fuel pump hum

 
Old 08-28-2017, 05:34 PM
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Default 12 volts direct to fuel pump relay plug,no fuel pump hum

i have been having problems with my 91 ford f150 5.8 not starting because fuel pump refuse to prime sometime,i have another post about that on this site.I directly ran 12 volts to fuel pump relay plug without the relay and nothing,not a hum.This is a brand new fuel pump. I might go out side tommorow and fuel pump may run for a few seconds and then no more.Could somebody give me an insight on this?
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Old 08-28-2017, 07:08 PM
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Have you considered that the new fuel pump may be defective?
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Old 08-28-2017, 08:27 PM
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thinking about going back to the fuel pump pigtail close to the tank and run test wire straight to the battery and see if fuel pump runs.then i'll know it is in the wiring.
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Old 08-28-2017, 09:59 PM
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If the new pump cost less than 150.00, I would suspect it.
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Old 08-29-2017, 10:43 AM
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What was the original problem that made you change the fuel pump ?
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Old 08-30-2017, 01:19 PM
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no start sometimes,fuel pump works some time ,sometime not,cuts off, no fuel pump hum,come back later,fuel pump hum and it starts.
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Old 08-31-2017, 06:06 AM
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So same problem now..
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Old 08-31-2017, 09:17 AM
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yes same ol problem.
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Old 08-31-2017, 09:37 AM
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So.. probably not the pump. Have you troubleshot the wiring ?
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Old 08-31-2017, 09:44 AM
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yes as best as i could,i have power to my fuel pump relay plug,also power to my fuel cut off switch,and both fuel and ecm relays are clicking on and off with the switch.inertia switch has power to green and yellow wire when switch is on.Also i jumpered inertia switch and no sound of fuel pump.

Last edited by icu1954; 08-31-2017 at 03:18 PM.
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