Fuel pump getting no power.

Tiny
JAMES W.
  • MEMBER
What's your email address, and I'll send you some PDF files of diagrams.
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
CJ MEDEVAC
  • EXPERT
ME TOO

WIFEY SAYS I WRITE TOO MUCH STUFF

IF I WHACKED ALL THE WIRES OFF OF MY CJ RADIO, WOULD IT STILL RUN. THE RADIO. Lol!

THE MEDIC
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Tuesday, December 19th, 2017 AT 6:38 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Shanepaye@hotmail. Com Thank you very much
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
Sorry for my lag storm and kids sport have me runnin in circles.
I will answer in order from my last post as best I can
1. Yes if I unplug the relay the pumps will stop but the relay buzzs upon reconnecting until I fully cycle the key
2. Ok sent my address
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
JAMES W.
  • MEMBER
Done deal!
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
Ok went out and double checked if I unplug the brown and green pigtails from them 2 relays is the only way both pumps will shut down
there is a 3rd relay with a grey pigtail that has no effect on the pumps that I have noticed
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Well here we go, I have tested continuity from the test port to the fuel pump relay. Tan w/lt grn, it was good, I then tested from both fuel pump relay and test port tan w/lt grn to pin 22 of the harness side of the connector, I had good clear continuity. I have tested the ground from pin 20 to the body of the truck and it was grounded good. When I ground the fuel pump relay at the test port the fuel pumps run and the truck will start. So somewhere some how the eec is not grounding the fuel pump relay. Is there anymore tests I can perform? My next question is when the key is turned to the on position are the pumps supposed to run constantly or are they supposed to shut off after a few seconds?
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
CJ MEDEVAC
  • EXPERT
ASEMaster6371----I THINK YOU NEED TO ANSWER THE "HANDS ON" STUFF

I'LL GET HIM THE DIAGRAMS WHEN I FINISH HERE

THE MEDIC
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
JAMES W.
  • MEMBER
The fuel pump should run for only a few seconds at "key on". The fuel pump relay is feed 12 volts with key on. The EEC computer "grounds" the relay coil to close the relay. From what you say, your computer appears to be bad.
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Got you CJ.

When you pulled the fuel pump relay and the pumps stopped, this means the control side of the relay is staying engaged meaning it is grounded 100% of the time. This is what we have to fix.

Does this have dual tanks? If it does, disconnect the switching valve and connect the relay and make sure the pumps are off. You may have a wiring issue down at the switching valve.

Roy
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Yeah I think your right, because before this happened (fuel pumps don't come on) the fuel pumps ran when the key was on for as long as it was on. Would that also explain the trouble starting before? It would start before as long as I turned the key from all the way off to start in one quick motion and even then it would crank a couple times to long. But every morning it would start like a new truck.
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
My valve is original ford so there is no electric on the valve at all it works off of fuel pressure
i have an in dash switch that turns power on to either in tank pickup pump
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
And would the fuel pumps staying on also be computer?
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
No, the switch operates a switching valve under the truck where the lines all meet. Take another look. If there is a switch on the dash, then there is electric under the truck.

Roy
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
JAMES W.
  • MEMBER
Let me know what you find.
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
Again this is an 87 all original. I had the valve out 3x already and there is no electrical on the valve what so ever
there are 2 springs within the valve that compress when the pickup pump pressurise against it
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
If it quit while four wheeling, have you checked the inertia switch? Its right next to the brake pedal just above it. Make sure it has continuity when pressed, and no cont, when tripped, if it tests otherwise, replace it.
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
Ford dual function reservoir (non electric tank switch valve)
i believe this is the tech name for what ive been calling a valve
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
SHANEPAYE
  • MEMBER
Inertia switch was not tripped, what controls the fuel pumps running for 3-4 seconds when the key is turned on? What would make them stay running?
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)
Tiny
DIXON1
  • MEMBER
Ok truck is now down to 1 tank I bypassed the dfr thinking it may have been recycling gas to the front tank. Original issue still there with the pumps running and the key off. I final took a chance while it was running and I cut the brown wire at the the fuel pump relay the motor never missed a beat so I then turn off the key and my pumps stopped. I then tried restarting 1st turning the ignition switch to the on position and paused to listen for the pumps rear tank and high pressure pump both worked and the truck restarted. I drove it 5 miles and evrything is still workin off the key, so this seems to have fixed the problem for now but I would like to find out what caused this if there is a direct ground short or what
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Tuesday, December 19th, 2017 AT 6:39 PM (Merged)

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