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03 silverado 2nd brand new fuel pump not pumping fuel

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Old December 31st, 2023, 5:08 PM
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Default 03 silverado 2nd brand new fuel pump not pumping fuel

I changed out old pump with a new one and it would turn on but not pump and I confirmed this right at the pump. Went and exchanged for another new one. This one does the same thing. Stuck it in a 5 gal bucket of gas and no gas coming out of ports. Am I missing something? What's the possibility of 2 bad pumps??
Old December 31st, 2023, 5:12 PM
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what do you mean by "turn on but not pump"? Did you check the fuses and relays before running out for parts?
Old December 31st, 2023, 5:16 PM
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Yes it's getting power. Pump hums but does not pump fuel out
Old December 31st, 2023, 5:20 PM
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maybe it's getting some power, but not enough.
https://www.ms-motorservice.com/int/...k-contact-1055
Old December 31st, 2023, 5:48 PM
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I have a .25 volt drop starting at 13.15 volts
Old December 31st, 2023, 5:52 PM
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volt drop where? I don't know what you measured or where you put your probes.
Old December 31st, 2023, 5:55 PM
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First checked voltage where I spliced new pump harness and then with pump on back proved the pins on connector while hooked up just like the article you sent said how to do
Old December 31st, 2023, 6:19 PM
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and that was with the pump on or humming in your case? and before that you checked that there was voltage on the harness with the ignition on?

If so then you probably have a bad ground. Measure resistance between the harness ground and some bare metal on the body or frame.
Old January 1st, 2024, 9:38 AM
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Was some resistance on ground wire. Cleaned up the ground point in the back and even added a 2nd ground wire just to make sure. Pump still hums but does not pump fuel
Old January 1st, 2024, 10:23 AM
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How much resistance? something doesn't add up.
if you have 13V on the power wire, and the pump is dropping 0.25V, that would mean you have 12.75V on the ground pin? So where are these 12.75V being lost?

Last edited by mountainmanjoe; January 1st, 2024 at 10:26 AM.


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