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Electrical 90 5.0 fuel relay problems

  • Thread starter Thread starter smashyaface
  • Start date Start date May 22, 2023
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smashyaface

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May 22, 2023
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  • May 22, 2023
  • #1
Okay I've just purchased a 90 fox body from family. On pickup fuel pump wouldn't prime. Got it home and started digging.

Inertia good. 12v both sides of that plug. Ignition good 12v there. 12v at injectors. Control side seems good.

Couldn't hear fuel pump relay click so bought one cause they're cheap. Swapped it but no go.
Jumped the pink/blk to 12v and pump runs. Fired up the car to see if it would run and it ran. Not the pump.

On my fuel pump relay my colors are green/yellow stripe which seems to be always hot. Pink/blk for fuel pump. Tan/Ltd blue and red.

I seem to be stuck and can't figure out why I can't get the relay to work? Maybe the new relay I bought is bad too? Been through the checklist several times and it doesn't seem to get me where I need to be. Any help would be appreciated.
 
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smashyaface

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May 22, 2023
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  • May 22, 2023
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#4 green/yellow stripe always hot
#3 pink/blk fuel pump
#2 red
#1 tan/light blue

Ignition on. No power to #3, 2 or 1
 
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smashyaface

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May 22, 2023
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  • May 22, 2023
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Also, tried to jump the test connector and that did not turn the fuel pump on either
 
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smashyaface

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May 22, 2023
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  • May 22, 2023
  • #4
Correction I have .5v on the red wire with ignition on. Tried putting the spare fuel pump relay in for the ecc relay same results.
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
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May 22, 2023
#5
  • May 22, 2023
  • #5
They are different relays so I do not believe they will interchange.

When you “jumped” the EEC test connector did you ground it? Just making sure as that is what you are supposed to do.

Take a look at this diagram:

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

So if there is no 12V+ on the tan / lt blue the you need to trace that back to the starter solenoid as it could be a blown fusible link.
 
Last edited: May 22, 2023
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