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Fuel Pump

Tiny
MATTHEWH
  • MEMBER
  • 2002 FORD EXPEDITION
  • V8
  • 2WD
  • AUTOMATIC
  • 133,000 MILES
Sometimes my fuel pump does not engage when I turn the key. When it does it starts fine and never stalls or runs rough. There are no trouble codes. I have already checked the relay. What could be causing it to work sporadically.
Tuesday, February 23rd, 2010 AT 10:27 AM

54 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
I need to know what engine size you have in truck to look over the right wiring diagram so I can try to help with what might be going on.
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Wednesday, February 24th, 2010 AT 10:06 AM
Tiny
MATTHEWH
  • MEMBER
  • 7 POSTS
It is the 4.6 L V8
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Wednesday, February 24th, 2010 AT 11:01 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok next time it won't start I would like you to check the inertia switch. It is on the right side (passenger) under the dash, see pic below. Once you find it simply push the white or red button on it and see if it starts. Otherwise I would have to say we need to check the wiring to the pump or check for power to and from the relay with a digital multi meter. Let me know what you find and we will take it from there.


https://www.2carpros.com/forum/automotive_pictures/249564_DSC01070_1.jpg

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Thursday, February 25th, 2010 AT 8:58 AM
Tiny
MATTHEWH
  • MEMBER
  • 7 POSTS
I have checked the Inertia switch, it is fine. I have learned something that might help you. I can keep turning the key from the off to run until I hear the pump run, then it starts. Sometimes it takes several times, but once I hear it run it starts right up.
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Thursday, February 25th, 2010 AT 9:48 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Have you checked out the PCM power relay? This is the switched power source for the fuel pump relay. This is in the junction box under the dash. If you have a digital multi meter then check if term 86 or the white wire with the light blue stripe is getting power as you turn the key on.
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Friday, February 26th, 2010 AT 10:02 AM
Tiny
MATTHEWH
  • MEMBER
  • 7 POSTS
Now the pump will not engage at all. I will test the wire you told me about tomorrow. Is it AC or DC?
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Thursday, March 4th, 2010 AT 6:51 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
It is all DC power. Let me know what you find and we will go from there.
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Friday, March 5th, 2010 AT 10:17 AM
Tiny
MATTHEWH
  • MEMBER
  • 7 POSTS
I checked the relay, it is getting power. I can feel it clicking when the engine is turned over. I will check the wire going to the fuel pump. Will it be the white wire with the blue stripe? Where in line would be the best place to access it? Thank you for your patience, I will add some more money to the forum for you.
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Monday, March 8th, 2010 AT 2:07 PM
Tiny
RACEFAN966
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It shows the wire to be pink with black stripe that powers the fuel pump. Let me know what you find and we will go from there.
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Tuesday, March 9th, 2010 AT 8:59 AM
Tiny
MATTHEWH
  • MEMBER
  • 7 POSTS
The Fuel pump is definitely getting power. My meter reads the pink with black stripped wire as getting power and I can hear it click when the key is turned but it does not run.
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Sunday, March 14th, 2010 AT 3:36 PM
Tiny
RACEFAN966
  • MECHANIC
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Ok so when it won't start does the pump get power? Have you replaced anything? Have you checked for spark?
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Monday, March 15th, 2010 AT 9:02 AM
Tiny
SIDNEY NOWDEN
  • MEMBER
  • 1 POST
I have a 2002 ford expedition, 4.6 v8, pulling up in my driveway and the truck went dead. They told me it was the fuel. So I replaced the fuel pump and the filter, but it keep blowing the fuse under the hood
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Wednesday, November 2nd, 2011 AT 6:09 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Which fuse?
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Tuesday, December 13th, 2011 AT 8:09 PM
Tiny
SOULSNAKE79
  • MEMBER
  • 5 POSTS
  • 2006 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 164,290 MILES
When I try to start my expedition it will crank but it won't start. I have determined that it is a fuel problem since there isn't any fuel at the rail. I have replaced the fuel filter, fuel pump, fuel pump driver module, crank position sensor, and both cam position sensors. I have also pulled the central junction box and checked the built in fuel pump relay to see if it was bad and it wasn't. What else should I be doing to get fuel to the engine
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The first thing you should be doing is using a fuel pressure gauge to know for sure what the pump is or isn't doing.
Check the Inertia switch to see if it has been tripped.
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
SOULSNAKE79
  • MEMBER
  • 5 POSTS
I checked the inertia switch and it wasn't tripped. I also checked to see if I was getting any voltage to the inertia switch and I am not. As far as the fuel pressure, when I pulled the main fuel line off of the rail and cycled the pump several times, there was not any fuel coming through the a in line. The only reason I pulled the main line is because I can't seem to be able to find the Schrader valve anywhere on the fuel rail.
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
I don't know how you can know an internal relay is good or not. You're just going to have to track it down with the wiring diagram.

https://www.2carpros.com/images/external/121819835.jpg.gif
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
SOULSNAKE79
  • MEMBER
  • 5 POSTS
I have the diagrams and I tried bypassing the fuel relay to see if that worked and it didn't. This is what leads me to believe it is something else.
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
That just makes no sense at all. You say you have no power at the Inertia switch and that comes directly from the relay and you say you jumped that out which would have put power directly to the Inertia switch. You're doing something wrong here. The fuel pump relay is not even accessible.
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)
Tiny
SOULSNAKE79
  • MEMBER
  • 5 POSTS
This is what I used as a guideline. I understand that the fuel relay is not accessible that is why I tried to jump the wires that come from the relay.
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Sunday, March 24th, 2019 AT 10:49 AM (Merged)

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