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Fuel Pump is not getting the correct voltage

Old 02-13-2013, 08:59 PM
  #1  
lavertue
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Default Fuel Pump is not getting the correct voltage

Okay, so I have a 1991 Mustang Gt 5.0. Well a few months back I lost all power to my fuel pump. I replaced the pump before checking to see if it had 12 volts. Well, when I tried to fire up the car after putting in the new pump, nothing. So After replacing the relay under my seat, checking the inertia switch I could not find the culprit. So I just ran a wire from up in the front of the car directly to my fuel pump. The wire gives it 12v when the car is on the on position. I ran the wire right up to the harness on the fuel pump and spliced into the wire right there, and boom it worked. Sort of... Well I keep going through fuel pumps and I know that it shouldn't run steady like it is. So my question is, does anyone have any thoughts as to where I need to check to see where I'm losing power. I checked it where the fuel pump is connected and it is not getting enough power. I also un-clipped the harness and checked it and same thing. I did not check it where the harness clips into the other harness. (The harness that goes from the fuel pump and the sending unit to the rest of the car.) So any body have any ideas where to start? And what to test?
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Old 02-13-2013, 09:12 PM
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mjr46
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you need to do voltage drop tests, with a dvom, here is a diagram, see if you have power from the fusible like to the relay, the inertia switch supplies power to the windings, and of course test all grounds

http://www.google.com/imgres?imgurl=...QEwBA&dur=2554
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Old 02-14-2013, 01:11 PM
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lxman1
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Originally Posted by lavertue View Post
Well I keep going through fuel pumps and I know that it shouldn't run steady like it is.
The pump should run constantly as long as the engine is running.
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Old 02-14-2013, 09:24 PM
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lavertue
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Originally Posted by lxman1 View Post
The pump should run constantly as long as the engine is running.
I mean when it primes, I just want to get back to the stock harness with the relays and inertia switch. It seems safer, haha. Dropping the tank tonight to go get my money back from this POS Advanced Auto fuel pump.
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Old 02-15-2013, 06:50 AM
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mjr46
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Originally Posted by lavertue View Post
I mean when it primes, I just want to get back to the stock harness with the relays and inertia switch. It seems safer, haha. Dropping the tank tonight to go get my money back from this POS Advanced Auto fuel pump.
try buying a walbro pump, unless of course you like doing the job over and over
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Old 02-15-2013, 11:13 AM
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lavertue
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Originally Posted by mjr46 View Post
try buying a walbro pump, unless of course you like doing the job over and over
This is the 5th time dropping the tank in 6 months, I'm growing tired of it. I was going to get a walbro pump anyways. Any suggestions on which one?
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Old 02-15-2013, 11:48 AM
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no reason not to get a 255lph, you have a return style system, excess back to the tank , can't go wrong, also it'll support future mods
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