Fuel pump relay?

Tiny
SEVENOF7
  • MEMBER
  • 1990 FORD F-150
  • V8
  • 4WD
  • MANUAL
  • 140,215 MILES
Fuel was staying on, changed relay now it will not run at all?
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Tuesday, April 14th, 2009 AT 8:21 PM

41 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Have you tried replacing the relay again? The pump may be going bad and burning up the relay. This guide can help with the fuel pump relay in the diagrams below.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

LH Side Of Engine Compartment, On Relay Bracket. Fuel pump relay is next to the EEC Relay. Check out the diagrams (Below). Please let us know what happens.
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Thursday, April 16th, 2009 AT 8:48 PM
Tiny
BLAZ85
  • MEMBER
  • 1990 FORD F-150
  • 4.9L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
Have a no crank situation with also no power to fuel pump or any accessories. New battery, headlights work chime sounds when key is inserted into ignition.
Could you provide the location of the ignition, fuel pump and EEC relays along with suggested testing procedures. I understand the these era Fords had problems with corrosion at the relays.

Thanks in advance for your reply!
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

I attached a pic below showing starter relay and EEC module locations. The EEC power relay will not prevent the starter from engaging but will stop fuel.

The EEC relay and fuel pump relay (I have no pic) is located on the left fender apron, on a relay assembly.

Here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know if this helps or if you have other questions.

Take care,
Joe
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
BLAZ85
  • MEMBER
A little update after I looked at the vehicle more closely. What the problem seems to be is there is no power to ignition and accessories when the key is turned to "run" or "start". I checked both EEC and fuel pump relays and they have power. In but no power on terminal that activates relay. We have a new battery and I jumped the starter relay and engine cranked over strongly. The headlights and horn work but none of the dash gauges, power locks or windows work when key is turned to "run". I checked several fuses in the fuse block that are "hot" when key is in "run" position and none had power. On a couple of occasions when key was turned to "start" it kind of "grunted" like the starter tried to engage. I think it is probably the ignition switch which I will change tomorrow.

What I need your help with is a wiring diagram to wiring associated with ignition switch so I can check for power in and power out to switch.

Thank you for your first replay and in advance for your reply on this request.
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

That does sound like it's the issue.

The first two pics below are of the starting system. I broke on pic into two parts so they are more readable. I did overlap them so you can follow them.

Next, the ignition switch actuator rod itself may be out of adjustment as well. Here are directions for adjustment:

___________________________________

1990 Ford Truck F 150 2WD Pickup L6-300 4.9L
Adjustments
Vehicle Starting and Charging Sensors and Switches - Starting and Charging Ignition Switch Adjustments
ADJUSTMENTS
Locking Pin Hole Location

see pic 3

1. ROTATE the ignition key back and forth to either side of lock, until a 1.98 mm (5/64-inch) drill bit can be inserted through the lockpin hole as far as possible (minimum 9.5mm (3/8 inch) ). The lock pin hole is located on the right of the switch next to the steering column tube.
2. Loosen the two ignition switch mounting nuts.
3. Turn the ignition to LOCK (feel for detent) and remove the ignition key.
4. Move the switch up and down along the column to locate the mid-position of rod lash. Tighten the two ignition switch mounting nuts (TOP NUT FIRST to minimize rod binding) to 4.51-7.34 N.M (40-65 in-lb).
5. Remove the drill bit from the ignition switch lockpin hole.
6. Plug in electrical connector and operate the lock cylinder to ensure the switch is positioned properly.
7. Confirm that all accessories are deactivated with ignition switch in OFF position, and that all accessories are operable in RUN position.

_______________________________

Let me know if that helps or if you have other questions.

Take care,
Joe
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
BLAZ85
  • MEMBER
Update: Well, it wasn't the ignition switch. Using your wiring diagram, I checked and had power to the switch. I checked the switch and seemed to make up correctly in all positions. What I found was that I had power under no load but lost power when load was applied. I finally identified the yellow wire feeding the switch. There were 3 yellow wires coming off the starter relay terminal but I finally identified the correct one with a continuity check. What I found buried down beside the battery box was a fusible link that had been replaced in the past. One end was connected with a wire nut. Apparently when my son installed the new battery, he bumped it and disturbed the connection to where it would not carry a load. I cleaned and tightened the connection and it fired right up.

Thanks so much for your help. Without that diagram, I don't know if I would have ever found the problem. Thanks again!
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
You are very welcome. I'm glad you got if fixed. That wasn't an easy one to find either. Regardless, as long as it's running, that's all that matters.

Thanks for letting me know and feel free to come back anytime in the future.

Take care,
Joe
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Tuesday, September 8th, 2020 AT 3:06 PM (Merged)
Tiny
SKYEWATCHER
  • MEMBER
  • 1990 FORD F-150
Engine Mechanical problem
1990 Ford F150 6 cyl Four Wheel Drive Manual

What controls the fuel pump relay switch(where does the signal come from
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Tuesday, September 8th, 2020 AT 3:07 PM (Merged)
Tiny
MATHIASO
  • MEMBER
Hello skyewatcher

The computer controls(energize) the fuel pump relay
base on the Profile Ignition Pick-up (PIP) sensor, which sends the crankshaft position information to the TFI-IV module. The TFI-IV module then sends this information to the EEC-IV module which energize the relay

Make also sure the fuse link W is in good condition.
(see diagram), will be sent to your email.


https://www.2carpros.com/forum/automotive_pictures/46384_0996b43f8020339a_2.jpg

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Tuesday, September 8th, 2020 AT 3:07 PM (Merged)
Tiny
CMILLER90
  • MEMBER
  • 1990 FORD F-150
  • 6 CYL
  • 4WD
  • MANUAL
  • 173,562 MILES
I am getting no power to my fuel pump, fuel pump relay, or my enertia switch no fuses are blown and I have checked over all the wires but there is a wire with a built in fuse going to the selinoid do you think that fuse could be blown cause the truck to not get any power to any of those elements or could there be something else causing it to do that?
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Tuesday, September 8th, 2020 AT 3:08 PM (Merged)
Tiny
2CEXPT
  • MEMBER
Its the 20ga blue fusible link from the starter relay powers the fuel pump-check and test -You could be on the right track
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+1
Tuesday, September 8th, 2020 AT 3:08 PM (Merged)
Tiny
DCOOK9719
  • MEMBER
You may have already checked this, but when this happened to me, it turned out to be the fuel tank selector switch. $7 a local junk yard and two screws later I was back on the road. Afterward I talked to the guy who sold me the truck and he said he had to replace the same switch twice before. I now carry and extra switch for emergencies
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Tuesday, September 8th, 2020 AT 3:08 PM (Merged)
Tiny
PATSIE
  • MEMBER
  • 1989 FORD F-150
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 10,500 MILES
I would like to know where the fuel pump relay would be located?
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Tuesday, September 8th, 2020 AT 3:08 PM (Merged)
Tiny
2CEXPT
  • MEMBER
Its located under shield at air cleaner support bracket.
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Tuesday, September 8th, 2020 AT 3:08 PM (Merged)
Tiny
EDWARD6984
  • MEMBER
  • 1989 FORD F-150
Electrical problem
1989 Ford F150 V8 Four Wheel Drive

I am not geting power to the yellow wire going to the fuel pump relay the red and tan have power but the yellow should have power at all times I cant figure out why it dont have power where would I find the fuse link in the wire
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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)
Tiny
2CEXPT
  • MEMBER
The fusible link is blue a 20 gauge wire at the starter relay. See below

Good Luck


https://www.2carpros.com/forum/automotive_pictures/12900_fuel_pump_relay_12.jpg

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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)
Tiny
CHRISTOPHER MASTERS
  • MEMBER
  • 1989 FORD F-150
  • 4.9L
  • 6 CYL
  • 2WD
  • MANUAL
  • 150,000 MILES
I have a truck that will not start. I wired the fuel pump directly to the fuse box to infuse that only comes on when the ignition is on. It will start and run for a few minutes then seems like it is flooding itself and shuts off. The yellow wire on the fuel pump relay has come out. Is there a way I can directly wire the fuel pump to the relay itself instead of the fuse box and if so will that work?
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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)
Tiny
KEN
  • ADMIN
Hey CHRISTOPHER,

You should rewire the fuel pump the way it is suppose to run, here is a wiring diagram which will help you fix the problem.

Please let me know who it goes so I can continue helping you.

Does the truck have dual tanks?

Best, Ken
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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)
Tiny
CHRISTOPHER MASTERS
  • MEMBER
Yes it does have dual tanks but I only use the front one.
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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)
Tiny
KEN
  • ADMIN
Hi Chris,

They had a big problem with the switching valve on those trucks which causes the fuel pressure to fail. We replaced them all the time. It is located on the frame rail on the drivers side just behind the front tank. This could be your problem as well.

Best, Ken
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Tuesday, September 8th, 2020 AT 3:10 PM (Merged)

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